diff --git a/development/Win32/packaging/AltInstaller/Updated.nsh b/development/Win32/packaging/AltInstaller/Updated.nsh
index 38ba95a2f1..35f6fb3d44 100644
--- a/development/Win32/packaging/AltInstaller/Updated.nsh
+++ b/development/Win32/packaging/AltInstaller/Updated.nsh
@@ -8,7 +8,7 @@ Function UpdateModifiedFiles
  File /r "${PRODUCT_SOURCEDIR}\Resources\locale" # always here
  File "${PRODUCT_SOURCEDIR}\Resources\configure.py"
  File "${PRODUCT_SOURCEDIR}\Resources\external_templates"
- #File "${PRODUCT_SOURCEDIR}\Resources\unicodesymbols"
+ File "${PRODUCT_SOURCEDIR}\Resources\symbols"
  SetOutPath "$INSTDIR\Resources\doc"
  File "${PRODUCT_SOURCEDIR}\Resources\doc\Customization.lyx"
  File "${PRODUCT_SOURCEDIR}\Resources\doc\EmbeddedObjects.lyx"
@@ -44,6 +44,8 @@ Function UpdateModifiedFiles
  File "${PRODUCT_SOURCEDIR}\Resources\man\tex2lyx.1"
  SetOutPath "$INSTDIR\Resources\templates"
  File "${PRODUCT_SOURCEDIR}\Resources\templates\ACM-siggraph.lyx"
+ SetOutPath "$INSTDIR\Resources\ui"
+ File "${PRODUCT_SOURCEDIR}\Resources\ui\stdcontext.inc"
 
 FunctionEnd
 
diff --git a/lib/symbols b/lib/symbols
index 66b8be98be..e32f50dfc9 100644
--- a/lib/symbols
+++ b/lib/symbols
@@ -128,13 +128,19 @@ vref              ref         none
 lyxnegspace       space       none
 lyxposspace       space       none
 !                 space       none
+negthinspace      space       none
 negmedspace       space       none
 negthickspace     space       none
 ,                 space       none
+thinspace         space       none
 :                 space       none
+medspace          space       none
 ;                 space       none
+thickspace        space       none
+enskip            space       none
 quad              space       none
 qquad             space       none
+hspace            space       none
 
 # styles
 displaystyle      style       0
diff --git a/lib/ui/stdcontext.inc b/lib/ui/stdcontext.inc
index 527df1f92d..14a0351244 100644
--- a/lib/ui/stdcontext.inc
+++ b/lib/ui/stdcontext.inc
@@ -188,6 +188,24 @@ Menuset
 		Item "Settings...|S" "next-inset-toggle"
 	End
 
+#
+# InsetMathSpace context menu
+#
+	Menu "context-mathspace"
+		Item "Thin Space|T" "next-inset-modify mathspace \thinspace{}"
+		Item "Medium Space|M" "next-inset-modify mathspace \medspace{}"
+		Item "Thick Space|h" "next-inset-modify mathspace \thickspace{}"
+		Item "Negative Thin Space|N" "next-inset-modify mathspace \negthinspace{}"
+		Item "Negative Medium Space|u" "next-inset-modify mathspace \negmedspace{}"
+		Item "Negative Thick Space|i" "next-inset-modify mathspace \negthickspace{}"
+		Item "Half Quad Space (Enskip)|k" "next-inset-modify mathspace \enskip{}"
+		Item "Quad Space|Q" "next-inset-modify mathspace \quad{}"
+		Item "Double Quad Space|u" "next-inset-modify mathspace \qquad{}"
+		Item "Custom Length|C" "command-sequence next-inset-modify mathspace \hspace{} \length 1in; next-inset-toggle"
+		Separator
+		Item "Settings...|S" "next-inset-toggle"
+	End
+
 #
 # InsetVSpace context menu
 #
diff --git a/src/LyXAction.cpp b/src/LyXAction.cpp
index 62ee53ad06..30e9425cf4 100644
--- a/src/LyXAction.cpp
+++ b/src/LyXAction.cpp
@@ -1473,10 +1473,14 @@ void LyXAction::init()
  * \var lyx::FuncCode lyx::LFUN_MATH_SPACE
  * \li Action: Inserts space into math expression.
  * \li Notion: Use spacebar after entering this space to change type of space.
- * \li Syntax: math-space [<TYPE>]
- * \li Params: <TYPE>: negative spaces: !|negmedspace|negthickspace \n
-                       positive spaces: ,|:|;|quad|qquad \n
+ * \li Syntax: math-space [<TYPE>] [<LEN>]
+ * \li Params: <TYPE>: negative spaces: !|negthinspace|negmedspace|negthickspace \n
+                       positive spaces: ,|thinspace|:|medspace|;|thickspace|enskip|quad|qquad \n
+                       custom space: hspace \n
                        "," used by default.
+                       Note that ! is equivalent to negthinspace, , = thinspace,
+                       : = medspace, and ; = thickspace.
+               <LEN>: length for custom spaces (hspace)
  * \li Origin: Andre, 25 Jul 2001; sanda, 16 Jun 2008
  * \endvar
  */
diff --git a/src/factory.cpp b/src/factory.cpp
index 4f6cb089a8..b75db6dbc9 100644
--- a/src/factory.cpp
+++ b/src/factory.cpp
@@ -320,7 +320,7 @@ Inset * createInsetHelper(Buffer & buf, FuncRequest const & cmd)
 				return 0;
 			
 			}
-			} //end LFUN_INSET_INSERT
+		} //end LFUN_INSET_INSERT
 
 		case LFUN_SPACE_INSERT: {
 			string const name = cmd.getArg(0);
@@ -330,12 +330,17 @@ Inset * createInsetHelper(Buffer & buf, FuncRequest const & cmd)
 				break;
 			}
 			InsetSpaceParams isp;
+			// The tests for isp.math might be disabled after a file format change
 			if (name == "normal")
 				isp.kind = InsetSpaceParams::NORMAL;
 			else if (name == "protected")
 				isp.kind = InsetSpaceParams::PROTECTED;
 			else if (name == "thin")
 				isp.kind = InsetSpaceParams::THIN;
+			else if (isp.math && name == "med")
+				isp.kind = InsetSpaceParams::MEDIUM;
+			else if (isp.math && name == "thick")
+				isp.kind = InsetSpaceParams::THICK;
 			else if (name == "quad")
 				isp.kind = InsetSpaceParams::QUAD;
 			else if (name == "qquad")
@@ -346,6 +351,10 @@ Inset * createInsetHelper(Buffer & buf, FuncRequest const & cmd)
 				isp.kind = InsetSpaceParams::ENSKIP;
 			else if (name == "negthinspace")
 				isp.kind = InsetSpaceParams::NEGTHIN;
+			else if (isp.math && name == "negmedspace")
+				isp.kind = InsetSpaceParams::NEGMEDIUM;
+			else if (isp.math && name == "negthickspace")
+				isp.kind = InsetSpaceParams::NEGTHICK;
 			else if (name == "hfill")
 				isp.kind = InsetSpaceParams::HFILL;
 			else if (name == "hfill*")
diff --git a/src/frontends/qt4/GuiHSpace.cpp b/src/frontends/qt4/GuiHSpace.cpp
index 60a279e9f9..2275eda40a 100644
--- a/src/frontends/qt4/GuiHSpace.cpp
+++ b/src/frontends/qt4/GuiHSpace.cpp
@@ -35,9 +35,10 @@ using namespace std;
 namespace lyx {
 namespace frontend {
 
-GuiHSpace::GuiHSpace(GuiView & lv)
-	: GuiDialog(lv, "space", qt_("Horizontal Space Settings"))
+GuiHSpace::GuiHSpace(GuiView & lv, bool math)
+	: GuiDialog(lv, math ? "mathspace" : "space", qt_("Horizontal Space Settings"))
 {
+	params_.math = math;
 	setupUi(this);
 
 	connect(okPB, SIGNAL(clicked()), this, SLOT(slotOK()));
@@ -86,8 +87,23 @@ void GuiHSpace::change_adaptor()
 }
 
 
+void GuiHSpace::setMath(bool custom)
+{
+	valueLE->setEnabled(custom);
+	unitCO->setEnabled(custom);
+	fillPatternCO->setEnabled(false);
+	keepCB->setToolTip(qt_("Insert the spacing even after a line break"));
+	keepCB->setEnabled(false);
+}
+
+
 void GuiHSpace::enableWidgets(int selection)
 {
+	if (params_.math) {
+		setMath(selection == 9);
+		changed();
+		return;
+	}
 	valueLE->setEnabled(selection == 7);
 	unitCO->setEnabled(selection == 7);
 	fillPatternCO->setEnabled(selection == 6);
@@ -120,6 +136,33 @@ static void setWidgetsFromHSpace(InsetSpaceParams const & params,
 			  QCheckBox * keep,
 			  QComboBox * fillPattern)
 {
+	spacing->clear();
+	if (params.math) {
+		spacing->addItem(qt_("Thin space"));
+		spacing->addItem(qt_("Medium space"));
+		spacing->addItem(qt_("Thick space"));
+		spacing->addItem(qt_("Negative thin space"));
+		spacing->addItem(qt_("Negative medium space"));
+		spacing->addItem(qt_("Negative thick space"));
+		spacing->addItem(qt_("Half Quad (0.5 em)"));
+		spacing->addItem(qt_("Quad (1 em)"));
+		spacing->addItem(qt_("Double Quad (2 em)"));
+		spacing->addItem(qt_("Custom"));
+		keep->setEnabled(false);
+		fillPattern->setEnabled(false);
+	} else {
+		spacing->addItem(qt_("Inter-word space"));
+		spacing->addItem(qt_("Thin space"));
+		spacing->addItem(qt_("Negative thin space"));
+		spacing->addItem(qt_("Half Quad (0.5 em)"));
+		spacing->addItem(qt_("Quad (1 em)"));
+		spacing->addItem(qt_("Double Quad (2 em)"));
+		spacing->addItem(qt_("Horizontal Fill"));
+		spacing->addItem(qt_("Custom"));
+		keep->setEnabled(true);
+		fillPattern->setEnabled(true);
+	}
+
 	int item = 0;
 	int pattern = 0;
 	bool protect = false;
@@ -129,64 +172,76 @@ static void setWidgetsFromHSpace(InsetSpaceParams const & params,
 			break;
 		case InsetSpaceParams::PROTECTED:
 			item = 0;
-			protect = true;
+			protect = !params.math;
 			break;
 		case InsetSpaceParams::THIN:
+			item = params.math ? 0 : 1;
+			break;
+		case InsetSpaceParams::MEDIUM:
 			item = 1;
 			break;
+		case InsetSpaceParams::THICK:
+			item = params.math ? 2 : 1;
+			break;
 		case InsetSpaceParams::NEGTHIN:
-			item = 2;
+			item = params.math ? 3 : 2;
+			break;
+		case InsetSpaceParams::NEGMEDIUM:
+			item = params.math ? 4 : 2;
+			break;
+		case InsetSpaceParams::NEGTHICK:
+			item = params.math ? 5 : 2;
 			break;
 		case InsetSpaceParams::ENSKIP:
-			item = 3;
+			item = params.math ? 6 : 3;
 			break;
 		case InsetSpaceParams::ENSPACE:
-			item = 3;
-			protect = true;
+			item = params.math ? 6 : 3;
+			protect = !params.math;
 			break;
 		case InsetSpaceParams::QUAD:
-			item = 4;
+			item = params.math ? 7 : 4;
 			break;
 		case InsetSpaceParams::QQUAD:
-			item = 5;
+			item = params.math ? 8 : 5;
 			break;
 		case InsetSpaceParams::HFILL:
-			item = 6;
+			item = params.math ? 3 : 6;
 			break;
 		case InsetSpaceParams::HFILL_PROTECTED:
-			item = 6;
-			protect = true;
+			item = params.math ? 3 : 6;
+			protect = !params.math;
 			break;
 		case InsetSpaceParams::DOTFILL:
-			item = 6;
+			item = params.math ? 3 : 6;
 			pattern = 1;
 			break;
 		case InsetSpaceParams::HRULEFILL:
-			item = 6;
+			item = params.math ? 3 : 6;
 			pattern = 2;
 			break;
 		case InsetSpaceParams::LEFTARROWFILL:
-			item = 6;
+			item = params.math ? 3 : 6;
 			pattern = 3;
 			break;
 		case InsetSpaceParams::RIGHTARROWFILL:
-			item = 6;
+			item = params.math ? 3 : 6;
 			pattern = 4;
 			break;
 		case InsetSpaceParams::UPBRACEFILL:
-			item = 6;
+			item = params.math ? 3 : 6;
 			pattern = 5;
 			break;
 		case InsetSpaceParams::DOWNBRACEFILL:
-			item = 6;
+			item = params.math ? 3 : 6;
 			pattern = 6;
 			break;
 		case InsetSpaceParams::CUSTOM:
-			item = 7;
+			item = params.math ? 9 : 7;
 			break;
 		case InsetSpaceParams::CUSTOM_PROTECTED:
-			item = 7;
-			protect = true;
+			item = params.math ? 9 : 7;
+			protect = !params.math;
 			break;
 	}
 	spacing->setCurrentIndex(item);
@@ -195,7 +250,7 @@ static void setWidgetsFromHSpace(InsetSpaceParams const & params,
 
 	Length::UNIT default_unit =
 			(lyxrc.default_papersize > 3) ? Length::CM : Length::IN;
-	if (item == 7)
+	if (item == (params.math ? 9 : 7))
 		lengthToWidgets(value, unit, params.length, default_unit);
 	else
 		lengthToWidgets(value, unit, "", default_unit);
@@ -203,9 +258,28 @@ static void setWidgetsFromHSpace(InsetSpaceParams const & params,
 
 
 static InsetSpaceParams setHSpaceFromWidgets(int spacing,
-	QLineEdit * value, LengthCombo * unit, bool keep, int fill)
+	QLineEdit * value, LengthCombo * unit, bool keep, int fill, bool math)
 {
-	InsetSpaceParams params;
+	InsetSpaceParams params(math);
+	if (math) {
+		switch (spacing) {
+		case 0: params.kind = InsetSpaceParams::THIN;      break;
+		case 1: params.kind = InsetSpaceParams::MEDIUM;    break;
+		case 2: params.kind = InsetSpaceParams::THICK;     break;
+		case 3: params.kind = InsetSpaceParams::NEGTHIN;   break;
+		case 4: params.kind = InsetSpaceParams::NEGMEDIUM; break;
+		case 5: params.kind = InsetSpaceParams::NEGTHICK;  break;
+		case 6: params.kind = InsetSpaceParams::ENSKIP;    break;
+		case 7: params.kind = InsetSpaceParams::QUAD;      break;
+		case 8: params.kind = InsetSpaceParams::QQUAD;     break;
+		case 9:
+			params.kind = InsetSpaceParams::CUSTOM;
+			params.length = Length(widgetsToLength(value, unit));
+			break;
+		}
+		return params;
+	}
+
 	switch (spacing) {
 		case 0:
 			if (keep)
@@ -265,7 +339,7 @@ void GuiHSpace::applyView()
 {
 	params_ = setHSpaceFromWidgets(spacingCO->currentIndex(),
 			valueLE, unitCO, keepCB->isChecked(),
-			fillPatternCO->currentIndex());
+			fillPatternCO->currentIndex(), params_.math);
 }
 
 
@@ -279,7 +353,11 @@ void GuiHSpace::updateContents()
 
 bool GuiHSpace::initialiseParams(string const & data)
 {
+	bool const math = params_.math;
 	InsetSpace::string2params(data, params_);
+	params_.math = math;
+	if (params_.math)
+		setMath(params_.kind == InsetSpaceParams::CUSTOM);
 	setButtonsValid(true);
 	return true;
 }
@@ -287,7 +365,7 @@ bool GuiHSpace::initialiseParams(string const & data)
 
 void GuiHSpace::clearParams()
 {
-	params_ = InsetSpaceParams();
+	params_ = InsetSpaceParams(params_.math);
 }
 
 
@@ -299,11 +377,15 @@ void GuiHSpace::dispatchParams()
 
 bool GuiHSpace::isValid()
 {
-	return spacingCO->currentIndex() != 7 || !valueLE->text().isEmpty();
+	return spacingCO->currentIndex() != (params_.math ? 9 : 7)
+		|| !valueLE->text().isEmpty();
 }
 
 
-Dialog * createGuiHSpace(GuiView & lv) { return new GuiHSpace(lv); }
+Dialog * createGuiMathHSpace(GuiView & lv) { return new GuiHSpace(lv, true); }
+
+
+Dialog * createGuiTextHSpace(GuiView & lv) { return new GuiHSpace(lv, false); }
 
 
 } // namespace frontend
diff --git a/src/frontends/qt4/GuiHSpace.h b/src/frontends/qt4/GuiHSpace.h
index ef4d214c74..2f15aedabf 100644
--- a/src/frontends/qt4/GuiHSpace.h
+++ b/src/frontends/qt4/GuiHSpace.h
@@ -24,7 +24,7 @@ class GuiHSpace : public GuiDialog, public Ui::HSpaceUi
 	Q_OBJECT
 
 public:
-	GuiHSpace(GuiView & lv);
+	GuiHSpace(GuiView & lv, bool math);
 
 private Q_SLOTS:
 	///
@@ -35,6 +35,8 @@ private Q_SLOTS:
 	void patternChanged();
 
 private:
+	///
+	void setMath(bool custom);
 	/// Apply from dialog
 	void applyView();
 	/// Update the dialog
diff --git a/src/frontends/qt4/GuiView.cpp b/src/frontends/qt4/GuiView.cpp
index 800b6e17b4..495f383869 100644
--- a/src/frontends/qt4/GuiView.cpp
+++ b/src/frontends/qt4/GuiView.cpp
@@ -1993,8 +1993,9 @@ bool GuiView::dispatch(FuncRequest const & cmd)
 			Inset * inset = getOpenInset(name);
 			if (inset) {
 				// put cursor in front of inset.
-				if (!view()->setCursorFromInset(inset))
+				if (!view()->setCursorFromInset(inset)) {
 					LASSERT(false, break);
+				}
 				
 				// useful if we are called from a dialog.
 				view()->cursor().beginUndoGroup();
@@ -2218,7 +2219,7 @@ char const * const dialognames[] = {
 "aboutlyx", "bibitem", "bibtex", "box", "branch", "changes", "character",
 "citation", "document", "errorlist", "ert", "external", "file",
 "findreplace", "float", "graphics", "include", "index", "info", "nomenclature", "label", "log",
-"mathdelimiter", "mathmatrix", "note", "paragraph", "prefs", "print", 
+"mathdelimiter", "mathmatrix", "mathspace", "note", "paragraph", "prefs", "print", 
 "ref", "sendto", "space", "spellchecker", "symbols", "tabular", "tabularcreate",
 
 #ifdef HAVE_LIBAIKSAURUS
@@ -2399,12 +2400,12 @@ Dialog * createGuiERT(GuiView & lv);
 Dialog * createGuiExternal(GuiView & lv);
 Dialog * createGuiFloat(GuiView & lv);
 Dialog * createGuiGraphics(GuiView & lv);
-Dialog * createGuiHSpace(GuiView & lv);
 Dialog * createGuiInclude(GuiView & lv);
 Dialog * createGuiInfo(GuiView & lv);
 Dialog * createGuiLabel(GuiView & lv);
 Dialog * createGuiListings(GuiView & lv);
 Dialog * createGuiLog(GuiView & lv);
+Dialog * createGuiMathHSpace(GuiView & lv);
 Dialog * createGuiMathMatrix(GuiView & lv);
 Dialog * createGuiNomenclature(GuiView & lv);
 Dialog * createGuiNote(GuiView & lv);
@@ -2420,6 +2421,7 @@ Dialog * createGuiSymbols(GuiView & lv);
 Dialog * createGuiTabularCreate(GuiView & lv);
 Dialog * createGuiTabular(GuiView & lv);
 Dialog * createGuiTexInfo(GuiView & lv);
+Dialog * createGuiTextHSpace(GuiView & lv);
 Dialog * createGuiToc(GuiView & lv);
 Dialog * createGuiThesaurus(GuiView & lv);
 Dialog * createGuiHyperlink(GuiView & lv);
@@ -2478,6 +2480,8 @@ Dialog * GuiView::build(string const & name)
 		return createGuiViewSource(*this);
 	if (name == "mathdelimiter")
 		return createGuiDelimiter(*this);
+	if (name == "mathspace")
+		return createGuiMathHSpace(*this);
 	if (name == "mathmatrix")
 		return createGuiMathMatrix(*this);
 	if (name == "note")
@@ -2493,7 +2497,7 @@ Dialog * GuiView::build(string const & name)
 	if (name == "sendto")
 		return createGuiSendTo(*this);
 	if (name == "space")
-		return createGuiHSpace(*this);
+		return createGuiTextHSpace(*this);
 	if (name == "spellchecker")
 		return createGuiSpellchecker(*this);
 	if (name == "symbols")
diff --git a/src/frontends/qt4/ui/HSpaceUi.ui b/src/frontends/qt4/ui/HSpaceUi.ui
index 613dfa20e9..5d6a7b5b8f 100644
--- a/src/frontends/qt4/ui/HSpaceUi.ui
+++ b/src/frontends/qt4/ui/HSpaceUi.ui
@@ -79,46 +79,6 @@
      <property name="toolTip" >
       <string>Supported spacing types</string>
      </property>
-     <item>
-      <property name="text" >
-       <string>Inter-word space</string>
-      </property>
-     </item>
-     <item>
-      <property name="text" >
-       <string>Thin space</string>
-      </property>
-     </item>
-     <item>
-      <property name="text" >
-       <string>Negative thin space</string>
-      </property>
-     </item>
-     <item>
-      <property name="text" >
-       <string>Half Quad (0.5 em)</string>
-      </property>
-     </item>
-     <item>
-      <property name="text" >
-       <string>Quad (1 em)</string>
-      </property>
-     </item>
-     <item>
-      <property name="text" >
-       <string>Double Quad (2 em)</string>
-      </property>
-     </item>
-     <item>
-      <property name="text" >
-       <string>Horizontal Fill</string>
-      </property>
-     </item>
-     <item>
-      <property name="text" >
-       <string>Custom</string>
-      </property>
-     </item>
     </widget>
    </item>
    <item row="1" column="0" >
diff --git a/src/insets/InsetSpace.cpp b/src/insets/InsetSpace.cpp
index f83880a2d6..8cb306bdb0 100644
--- a/src/insets/InsetSpace.cpp
+++ b/src/insets/InsetSpace.cpp
@@ -20,6 +20,7 @@
 #include "Dimension.h"
 #include "FuncRequest.h"
 #include "FuncStatus.h"
+#include "LaTeXFeatures.h"
 #include "Length.h"
 #include "Lexer.h"
 #include "MetricsInfo.h"
@@ -28,6 +29,7 @@
 #include "support/debug.h"
 #include "support/docstream.h"
 #include "support/gettext.h"
+#include "support/lassert.h"
 #include "support/lstrings.h"
 
 #include "frontends/Application.h"
@@ -75,6 +77,12 @@ docstring InsetSpace::toolTip(BufferView const &, int, int) const
 	case InsetSpaceParams::THIN:
 		message = _("Thin Space");
 		break;
+	case InsetSpaceParams::MEDIUM:
+		message = _("Medium Space");
+		break;
+	case InsetSpaceParams::THICK:
+		message = _("Thick Space");
+		break;
 	case InsetSpaceParams::QUAD:
 		message = _("Quad Space");
 		break;
@@ -90,6 +98,12 @@ docstring InsetSpace::toolTip(BufferView const &, int, int) const
 	case InsetSpaceParams::NEGTHIN:
 		message = _("Negative Thin Space");
 		break;
+	case InsetSpaceParams::NEGMEDIUM:
+		message = _("Negative Mwedium Space");
+		break;
+	case InsetSpaceParams::NEGTHICK:
+		message = _("Negative Thick Space");
+		break;
 	case InsetSpaceParams::HFILL:
 		message = _("Horizontal Fill");
 		break;
@@ -131,10 +145,13 @@ void InsetSpace::doDispatch(Cursor & cur, FuncRequest & cmd)
 {
 	switch (cmd.action) {
 
-	case LFUN_INSET_MODIFY: {
+	case LFUN_INSET_MODIFY:
 		string2params(to_utf8(cmd.argument()), params_);
 		break;
-	}
+
+	case LFUN_INSET_DIALOG_UPDATE:
+		cur.bv().updateDialog("space", params2string(params()));
+		break;
 
 	case LFUN_MOUSE_RELEASE:
 		if (!cur.selection() && cmd.button() == mouse_button::button1)
@@ -159,6 +176,8 @@ bool InsetSpace::getStatus(Cursor & cur, FuncRequest const & cmd,
 			string2params(to_utf8(cmd.argument()), params);
 			status.setOnOff(params_.kind == params.kind);
 		}
+		// fall through
+	case LFUN_INSET_DIALOG_UPDATE:
 		status.setEnabled(true);
 		return true;
 	default:
@@ -196,6 +215,14 @@ void InsetSpace::metrics(MetricsInfo & mi, Dimension & dim) const
 		case InsetSpaceParams::NEGTHIN:
 			dim.wid = fm.width(char_type('M')) / 6;
 			break;
+		case InsetSpaceParams::MEDIUM:
+		case InsetSpaceParams::NEGMEDIUM:
+			dim.wid = fm.width(char_type('M')) / 4;
+			break;
+		case InsetSpaceParams::THICK:
+		case InsetSpaceParams::NEGTHICK:
+			dim.wid = fm.width(char_type('M')) / 2;
+			break;
 		case InsetSpaceParams::PROTECTED:
 		case InsetSpaceParams::NORMAL:
 			dim.wid = fm.width(char_type(' '));
@@ -269,12 +296,12 @@ void InsetSpace::draw(PainterInfo & pi, int x, int y) const
 
 		if (params_.kind == InsetSpaceParams::HFILL) {
 			pi.pain.line(x0, y1, x0, y0, Color_added_space);
-			pi.pain.line(x0, y2 , x1, y2, Color_added_space,
+			pi.pain.line(x0, y2, x1, y2, Color_added_space,
 				frontend::Painter::line_onoffdash);
 			pi.pain.line(x1, y1, x1, y0, Color_added_space);
 		} else if (params_.kind == InsetSpaceParams::HFILL_PROTECTED) {
 			pi.pain.line(x0, y1, x0, y0, Color_latex);
-			pi.pain.line(x0, y2 , x1, y2, Color_latex,
+			pi.pain.line(x0, y2, x1, y2, Color_latex,
 				frontend::Painter::line_onoffdash);
 			pi.pain.line(x1, y1, x1, y0, Color_latex);
 		} else if (params_.kind == InsetSpaceParams::DOTFILL) {
@@ -344,6 +371,8 @@ void InsetSpace::draw(PainterInfo & pi, int x, int y) const
 	if (params_.kind == InsetSpaceParams::PROTECTED ||
 	    params_.kind == InsetSpaceParams::ENSPACE ||
 	    params_.kind == InsetSpaceParams::NEGTHIN ||
+	    params_.kind == InsetSpaceParams::NEGMEDIUM ||
+	    params_.kind == InsetSpaceParams::NEGTHICK ||
 	    params_.kind == InsetSpaceParams::CUSTOM_PROTECTED)
 		pi.pain.lines(xp, yp, 4, Color_latex);
 	else
@@ -364,6 +393,12 @@ void InsetSpaceParams::write(ostream & os) const
 	case InsetSpaceParams::THIN:
 		os <<  "\\thinspace{}";
 		break;
+	case InsetSpaceParams::MEDIUM:
+		os <<  "\\medspace{}";
+		break;
+	case InsetSpaceParams::THICK:
+		os <<  "\\thickspace{}";
+		break;
 	case InsetSpaceParams::QUAD:
 		os <<  "\\quad{}";
 		break;
@@ -379,6 +414,12 @@ void InsetSpaceParams::write(ostream & os) const
 	case InsetSpaceParams::NEGTHIN:
 		os <<  "\\negthinspace{}";
 		break;
+	case InsetSpaceParams::NEGMEDIUM:
+		os <<  "\\negmedspace{}";
+		break;
+	case InsetSpaceParams::NEGTHICK:
+		os <<  "\\negthickspace{}";
+		break;
 	case InsetSpaceParams::HFILL:
 		os <<  "\\hfill{}";
 		break;
@@ -422,12 +463,17 @@ void InsetSpaceParams::read(Lexer & lex)
 	string command;
 	lex >> command;
 
+	// The tests for math might be disabled after a file format change
 	if (command == "\\space{}")
 		kind = InsetSpaceParams::NORMAL;
 	else if (command == "~")
 		kind = InsetSpaceParams::PROTECTED;
 	else if (command == "\\thinspace{}")
 		kind = InsetSpaceParams::THIN;
+	else if (math && command == "\\medspace{}")
+		kind = InsetSpaceParams::MEDIUM;
+	else if (math && command == "\\thickspace{}")
+		kind = InsetSpaceParams::THICK;
 	else if (command == "\\quad{}")
 		kind = InsetSpaceParams::QUAD;
 	else if (command == "\\qquad{}")
@@ -438,6 +484,10 @@ void InsetSpaceParams::read(Lexer & lex)
 		kind = InsetSpaceParams::ENSKIP;
 	else if (command == "\\negthinspace{}")
 		kind = InsetSpaceParams::NEGTHIN;
+	else if (math && command == "\\negmedspace{}")
+		kind = InsetSpaceParams::NEGMEDIUM;
+	else if (math && command == "\\negthickspace{}")
+		kind = InsetSpaceParams::NEGTHICK;
 	else if (command == "\\hfill{}")
 		kind = InsetSpaceParams::HFILL;
 	else if (command == "\\hspace*{\\fill}")
@@ -492,6 +542,12 @@ int InsetSpace::latex(odocstream & os, OutputParams const & runparams) const
 	case InsetSpaceParams::THIN:
 		os << (runparams.free_spacing ? " " : "\\,");
 		break;
+	case InsetSpaceParams::MEDIUM:
+		os << (runparams.free_spacing ? " " : "\\:");
+		break;
+	case InsetSpaceParams::THICK:
+		os << (runparams.free_spacing ? " " : "\\;");
+		break;
 	case InsetSpaceParams::QUAD:
 		os << (runparams.free_spacing ? " " : "\\quad{}");
 		break;
@@ -507,6 +563,12 @@ int InsetSpace::latex(odocstream & os, OutputParams const & runparams) const
 	case InsetSpaceParams::NEGTHIN:
 		os << (runparams.free_spacing ? " " : "\\negthinspace{}");
 		break;
+	case InsetSpaceParams::NEGMEDIUM:
+		os << (runparams.free_spacing ? " " : "\\negmedspace{}");
+		break;
+	case InsetSpaceParams::NEGTHICK:
+		os << (runparams.free_spacing ? " " : "\\negthickspace{}");
+		break;
 	case InsetSpaceParams::HFILL:
 		os << (runparams.free_spacing ? " " : "\\hfill{}");
 		break;
@@ -592,7 +654,11 @@ int InsetSpace::docbook(odocstream & os, OutputParams const &) const
 	case InsetSpaceParams::PROTECTED:
 	case InsetSpaceParams::ENSPACE:
 	case InsetSpaceParams::THIN:
+	case InsetSpaceParams::MEDIUM:
+	case InsetSpaceParams::THICK:
 	case InsetSpaceParams::NEGTHIN:
+	case InsetSpaceParams::NEGMEDIUM:
+	case InsetSpaceParams::NEGTHICK:
 		os << "&nbsp;";
 		break;
 	case InsetSpaceParams::HFILL:
@@ -617,6 +683,14 @@ int InsetSpace::docbook(odocstream & os, OutputParams const &) const
 }
 
 
+void InsetSpace::validate(LaTeXFeatures & features) const
+{
+	if (params_.kind == InsetSpaceParams::NEGMEDIUM ||
+	    params_.kind == InsetSpaceParams::NEGTHICK) 
+		features.require("amsmath");
+}
+
+
 void InsetSpace::tocString(odocstream & os) const
 {
 	plaintext(os, OutputParams(0));
@@ -652,7 +726,14 @@ void InsetSpace::string2params(string const & in, InsetSpaceParams & params)
 	Lexer lex;
 	lex.setStream(data);
 	lex.setContext("InsetSpace::string2params");
-	lex >> "space";
+	lex.next();
+	string const name = lex.getString();
+	if (name == "mathspace")
+		params.math = true;
+	else {
+		params.math = false;
+		LASSERT(name == "space", /**/);
+	}
 
 	// There are cases, such as when we are called via getStatus() from
 	// Dialog::canApply(), where we are just called with "space" rather
@@ -665,6 +746,8 @@ void InsetSpace::string2params(string const & in, InsetSpaceParams & params)
 string InsetSpace::params2string(InsetSpaceParams const & params)
 {
 	ostringstream data;
+	if (params.math)
+		data << "math";
 	data << "space" << ' ';
 	params.write(data);
 	return data.str();
diff --git a/src/insets/InsetSpace.h b/src/insets/InsetSpace.h
index 7607b09324..27ea07dd67 100644
--- a/src/insets/InsetSpace.h
+++ b/src/insets/InsetSpace.h
@@ -33,16 +33,24 @@ public:
 		PROTECTED,
 		/// Thin space ('\,')
 		THIN,
+		/// Medium space ('\:')
+		MEDIUM,
+		/// Thick space ('\;')
+		THICK,
 		/// \quad (1em)
 		QUAD,
 		/// \qquad (2em)
 		QQUAD,
-		/// \enspace (0.5em unbreakable)
+		/// \enskip (0.5em unbreakable)
 		ENSPACE,
 		/// \enspace (0.5em breakable)
 		ENSKIP,
 		/// Negative thin space ('\negthinspace')
 		NEGTHIN,
+		/// Negative medium space ('\negmedspace')
+		NEGMEDIUM,
+		/// Negative thick space ('\negthickspace')
+		NEGTHICK,
 		/// rubber length
 		HFILL,
 		/// \hspace*{\fill}
@@ -65,7 +73,7 @@ public:
 		CUSTOM_PROTECTED
 	};
 	///
-	InsetSpaceParams() : kind(NORMAL), length(Length()) {}
+	InsetSpaceParams(bool m = false) : kind(NORMAL), math(m) {}
 	///
 	void write(std::ostream & os) const;
 	///
@@ -74,6 +82,11 @@ public:
 	Kind kind;
 	///
 	Length length;
+	/**
+	 * Whether these params are to be used in mathed.
+	 * This determines the set of valid kinds.
+	 */
+	bool math;
 };
 
 
@@ -99,7 +112,6 @@ public:
 	///
 	Length length() const;
 
-private:
 	///
 	docstring toolTip(BufferView const & bv, int x, int y) const;
 	///
@@ -116,6 +128,8 @@ private:
 	int plaintext(odocstream &, OutputParams const &) const;
 	///
 	int docbook(odocstream &, OutputParams const &) const;
+	///
+	void validate(LaTeXFeatures & features) const;
 	/// the string that is passed to the TOC
 	void tocString(odocstream &) const;
 	///
@@ -137,13 +151,16 @@ private:
 	bool isSpace() const { return true; }
 	///
 	docstring contextMenu(BufferView const & bv, int x, int y) const;
+protected:
 	///
 	Inset * clone() const { return new InsetSpace(*this); }
 	///
 	void doDispatch(Cursor & cur, FuncRequest & cmd);
+public:
 	///
 	bool getStatus(Cursor & cur, FuncRequest const & cmd, FuncStatus &) const;
 
+private:
 	///
 	InsetSpaceParams params_;
 };
diff --git a/src/mathed/InsetMathNest.cpp b/src/mathed/InsetMathNest.cpp
index ffde2ad45f..b1dcf87248 100644
--- a/src/mathed/InsetMathNest.cpp
+++ b/src/mathed/InsetMathNest.cpp
@@ -835,7 +835,6 @@ void InsetMathNest::doDispatch(Cursor & cur, FuncRequest & cmd)
 		break;
 
 	//case LFUN_SERVER_GET_XY:
-	//	sprintf(dispatch_buffer, "%d %d",);
 	//	break;
 
 	case LFUN_SERVER_SET_XY: {
@@ -1033,15 +1032,18 @@ void InsetMathNest::doDispatch(Cursor & cur, FuncRequest & cmd)
 
 	case LFUN_SPACE_INSERT:
 		cur.recordUndoSelection();
-		cur.insert(MathAtom(new InsetMathSpace(from_ascii(","))));
+		cur.insert(MathAtom(new InsetMathSpace));
 		break;
 
 	case LFUN_MATH_SPACE:
 		cur.recordUndoSelection();
 		if (cmd.argument().empty())
-			cur.insert(MathAtom(new InsetMathSpace(from_ascii(","))));
-		else
-			cur.insert(MathAtom(new InsetMathSpace(cmd.argument())));
+			cur.insert(MathAtom(new InsetMathSpace));
+		else {
+			string const name = cmd.getArg(0);
+			string const len = cmd.getArg(1);
+			cur.insert(MathAtom(new InsetMathSpace(name, len)));
+		}
 		break;
 
 	case LFUN_ERT_INSERT:
@@ -1109,6 +1111,9 @@ void InsetMathNest::doDispatch(Cursor & cur, FuncRequest & cmd)
 		if (name == "ref") {
 			InsetMathRef tmp(name);
 			data = tmp.createDialogStr(to_utf8(name));
+		} else if (name == "mathspace") {
+			InsetMathSpace tmp;
+			data = tmp.createDialogStr();
 		}
 		cur.bv().showDialog(to_utf8(name), data);
 		break;
@@ -1252,7 +1257,7 @@ bool InsetMathNest::getStatus(Cursor & cur, FuncRequest const & cmd,
 		// getStatus is not called with a valid reference and the
 		// dialog would not be applyable.
 		string const name = cmd.getArg(0);
-		flag.setEnabled(name == "ref");
+		flag.setEnabled(name == "ref" || name == "mathspace");
 		break;
 	}
 
diff --git a/src/mathed/InsetMathSpace.cpp b/src/mathed/InsetMathSpace.cpp
index b9286087cf..25e2303d62 100644
--- a/src/mathed/InsetMathSpace.cpp
+++ b/src/mathed/InsetMathSpace.cpp
@@ -12,63 +12,101 @@
 
 #include "InsetMathSpace.h"
 #include "MathData.h"
+#include "MathFactory.h"
 #include "MathStream.h"
+#include "MathSupport.h"
 
+#include "BufferView.h"
+#include "Cursor.h"
+#include "FuncRequest.h"
+#include "FuncStatus.h"
 #include "LaTeXFeatures.h"
 
+#include "insets/InsetSpace.h"
+
+#include "frontends/Application.h"
 #include "frontends/Painter.h"
 
+#include "support/lassert.h"
+
 using namespace std;
 
 namespace lyx {
 
-char const * latex_mathspace[] = {
-	"!", "negmedspace", "negthickspace",  // negative space
-	",", ":", ";", "quad", "qquad",       // positive space
-	"lyxnegspace", "lyxposspace"          // LyX special ("unvisible space")
-};
-
-int const nSpace = sizeof(latex_mathspace)/sizeof(char *);
-
 namespace {
 
-int spaceToWidth(int space)
-{
-	switch (space) {
-		case 0: return 6;
-		case 1: return 8;
-		case 2: return 10;
-		case 3: return 6;
-		case 4: return 8;
-		case 5: return 10;
-		case 6: return 20;
-		case 7: return 40;
-		case 8: return -2;
-		case 9: return  2;
-		default: return 6;
-	}
-}
+struct SpaceInfo {
+	string name;
+	int width;
+	InsetSpaceParams::Kind kind;
+	bool negative;
+	bool visible;
+	bool custom;
+};
+
+SpaceInfo space_info[] = {
+	// name           width kind                         negative visible custom
+	{"!",              6,   InsetSpaceParams::NEGTHIN,   true,    true,   false},
+	{"negthinspace",   6,   InsetSpaceParams::NEGTHIN,   true,    true,   false},
+	{"negmedspace",    8,   InsetSpaceParams::NEGMEDIUM, true,    true,   false},
+	{"negthickspace", 10,   InsetSpaceParams::NEGTHICK,  true,    true,   false},
+	{",",              6,   InsetSpaceParams::THIN,      false,   true,   false},
+	{"thinspace",      6,   InsetSpaceParams::THIN,      false,   true,   false},
+	{":",              8,   InsetSpaceParams::MEDIUM,    false,   true,   false},
+	{"medspace",       8,   InsetSpaceParams::MEDIUM,    false,   true,   false},
+	{";",             10,   InsetSpaceParams::THICK,     false,   true,   false},
+	{"thickspace",    10,   InsetSpaceParams::THICK,     false,   true,   false},
+	{"enskip",        10,   InsetSpaceParams::ENSKIP,    false,   true,   false},
+	{"quad",          20,   InsetSpaceParams::QUAD,      false,   true,   false},
+	{"qquad",         40,   InsetSpaceParams::QQUAD,     false,   true,   false},
+	{"lyxnegspace",   -2,   InsetSpaceParams::NEGTHIN,   true,    false,  false},
+	{"lyxposspace",    2,   InsetSpaceParams::THIN,      false,   false,  false},
+	{"hspace",         0,   InsetSpaceParams::CUSTOM,    false,   true,   true},
+};
+
+int const nSpace = sizeof(space_info)/sizeof(SpaceInfo);
+int const defaultSpace = 4;
 
 } // anon namespace
 
-InsetMathSpace::InsetMathSpace(int sp)
-	: space_(sp)
+InsetMathSpace::InsetMathSpace()
+	: space_(defaultSpace)
 {
-	dim_.asc = 4;
-	dim_.des = 0;
-	dim_.wid = spaceToWidth(space_);
 }
 
 
-InsetMathSpace::InsetMathSpace(docstring const & name)
-	: space_(1)
+InsetMathSpace::InsetMathSpace(string const & name, string const & length)
+	: space_(defaultSpace)
 {
-	dim_.asc = 4;
-	dim_.des = 0;
 	for (int i = 0; i < nSpace; ++i)
-		if (latex_mathspace[i] == name)
+		if (space_info[i].name == name) {
 			space_ = i;
-	dim_.wid = spaceToWidth(space_);
+			break;
+		}
+	if (space_info[space_].custom) {
+		length_ = Length(length);
+		if (length_.zero() || length_.empty()) {
+			length_.value(1.0);
+			length_.unit(Length::EM);
+		}
+	}
+}
+
+
+InsetMathSpace::InsetMathSpace(Length const & length)
+	: space_(defaultSpace), length_(length)
+{
+	for (int i = 0; i < nSpace; ++i)
+		if (space_info[i].name == "hspace") {
+			space_ = i;
+			break;
+		}
+}
+
+
+InsetMathSpace::~InsetMathSpace()
+{
+	hideDialogs("mathspace", this);
 }
 
 
@@ -78,9 +116,16 @@ Inset * InsetMathSpace::clone() const
 }
 
 
-void InsetMathSpace::metrics(MetricsInfo &, Dimension & dim) const
+void InsetMathSpace::metrics(MetricsInfo & mi, Dimension & dim) const
 {
-	dim = dim_;
+	dim.asc = 4;
+	dim.des = 0;
+	if (space_info[space_].custom)
+		dim.wid = abs(length_.inPixels(
+				mi.base.textwidth,
+				mathed_char_width(mi.base.font, 'M')));
+	else
+		dim.wid = space_info[space_].width;
 }
 
 
@@ -88,36 +133,45 @@ void InsetMathSpace::draw(PainterInfo & pi, int x, int y) const
 {
 	// Sadly, HP-UX CC can't handle that kind of initialization.
 	// XPoint p[4] = {{++x, y-3}, {x, y}, {x+width-2, y}, {x+width-2, y-3}};
-	if (space_ >= nSpace - 2)
+	if (!space_info[space_].visible)
 		return;
 
+	Dimension const dim = dimension(*pi.base.bv);
 	int xp[4];
 	int yp[4];
-	int w = dim_.wid;
+	int w = dim.wid;
 
 	xp[0] = ++x;        yp[0] = y - 3;
 	xp[1] = x;          yp[1] = y;
 	xp[2] = x + w - 2;  yp[2] = y;
 	xp[3] = x + w - 2;  yp[3] = y - 3;
 
-	pi.pain.lines(xp, yp, 4, (space_ < 3) ? Color_latex : Color_math);
+	pi.pain.lines(xp, yp, 4,
+			space_info[space_].custom ?
+			Color_special :
+			(isNegative() ? Color_latex : Color_math));
 }
 
 
 void InsetMathSpace::incSpace()
 {
-	space_ = (space_ + 1) % (nSpace - 2);
-	dim_.wid = spaceToWidth(space_);
+	int const oldwidth = space_info[space_].width;
+	do
+		space_ = (space_ + 1) % nSpace;
+	while ((space_info[space_].width == oldwidth && !space_info[space_].custom) ||
+	       !space_info[space_].visible);
+	if (space_info[space_].custom && (length_.zero() || length_.empty())) {
+		length_.value(1.0);
+		length_.unit(Length::EM);
+	}
 }
 
 
 void InsetMathSpace::validate(LaTeXFeatures & features) const
 {
-	if (space_ >= 0 && space_< nSpace) {
-		if ((latex_mathspace[space_] == string("negmedspace"))
-		 || (latex_mathspace[space_] == string("negthickspace")))
-			features.require("amsmath");
-	}
+	if (space_info[space_].name == "negmedspace" ||
+	    space_info[space_].name == "negthickspace")
+		features.require("amsmath");
 }
 
 
@@ -146,12 +200,94 @@ void InsetMathSpace::normalize(NormalStream & os) const
 
 void InsetMathSpace::write(WriteStream & os) const
 {
-	if (space_ >= 0 && space_ < nSpace) {
-		MathEnsurer ensurer(os);
-		os << '\\' << latex_mathspace[space_];
+	// no MathEnsurer - all kinds work in text and math mode
+	os << '\\' << space_info[space_].name.c_str();
+	if (space_info[space_].custom)
+		os << '{' << length_.asLatexString().c_str() << '}';
+	else
 		os.pendingSpace(true);
+}
+
+
+string const InsetMathSpace::createDialogStr() const
+{
+	LASSERT(space_info[space_].visible, /**/);
+	InsetSpaceParams isp(true);
+	isp.kind = space_info[space_].kind;
+	isp.length = length_;
+	return InsetSpace::params2string(isp);
+}
+
+
+docstring InsetMathSpace::contextMenu(BufferView const &, int, int) const
+{
+	return from_ascii("context-mathspace");
+}
+
+
+bool InsetMathSpace::getStatus(Cursor & cur, FuncRequest const & cmd,
+                               FuncStatus & status) const
+{
+	switch (cmd.action) {
+	// we handle these
+	case LFUN_INSET_MODIFY:
+	case LFUN_INSET_DIALOG_UPDATE:
+	case LFUN_MOUSE_RELEASE:
+	case LFUN_MOUSE_PRESS:
+	case LFUN_MOUSE_MOTION:
+		status.setEnabled(true);
+		return true;
+	default:
+		bool retval = InsetMath::getStatus(cur, cmd, status);
+		return retval;
 	}
 }
 
 
+void InsetMathSpace::doDispatch(Cursor & cur, FuncRequest & cmd)
+{
+	switch (cmd.action) {
+	case LFUN_INSET_MODIFY:
+		if (cmd.getArg(0) == "mathspace") {
+			MathData ar;
+			if (createInsetMath_fromDialogStr(cmd.argument(), ar)) {
+				*this = *ar[0].nucleus()->asSpaceInset();
+				break;
+			}
+		}
+		cur.undispatched();
+		break;
+
+	case LFUN_INSET_DIALOG_UPDATE:
+		cur.bv().updateDialog("mathspace", createDialogStr());
+		break;
+
+	case LFUN_MOUSE_RELEASE:
+		if (cmd.button() == mouse_button::button1) {
+			string const data = createDialogStr();
+			cur.bv().showDialog("mathspace", data, this);
+			break;
+		}
+		cur.undispatched();
+		break;
+
+	case LFUN_MOUSE_PRESS:
+	case LFUN_MOUSE_MOTION:
+		// eat other mouse commands
+		break;
+
+	default:
+		InsetMath::doDispatch(cur, cmd);
+		break;
+	}
+}
+
+
+bool InsetMathSpace::isNegative() const
+{
+	if (space_info[space_].custom)
+		return length_.value() < 0;
+	return space_info[space_].negative;
+}
+
 } // namespace lyx
diff --git a/src/mathed/InsetMathSpace.h b/src/mathed/InsetMathSpace.h
index 579f29a3ab..4c3bfd2b47 100644
--- a/src/mathed/InsetMathSpace.h
+++ b/src/mathed/InsetMathSpace.h
@@ -13,6 +13,7 @@
 #define MATH_SPACEINSET_H
 
 #include "InsetMath.h"
+#include "Length.h"
 
 
 namespace lyx {
@@ -22,9 +23,13 @@ namespace lyx {
 class InsetMathSpace : public InsetMath {
 public:
 	///
-	explicit InsetMathSpace(int sp);
+	explicit InsetMathSpace();
 	///
-	explicit InsetMathSpace(docstring const & name);
+	explicit InsetMathSpace(std::string const & name, std::string const & length);
+	///
+	explicit InsetMathSpace(Length const & length);
+	///
+	~InsetMathSpace();
 	///
 	InsetMathSpace const * asSpaceInset() const { return this; }
 	///
@@ -48,12 +53,25 @@ public:
 	void octave(OctaveStream &) const;
 	///
 	void write(WriteStream & os) const;
+	/// generate something that will be understood by the Dialogs.
+	std::string const createDialogStr() const;
+	///
+	EDITABLE editable() const { return IS_EDITABLE; }
+	///
+	docstring contextMenu(BufferView const &, int, int) const;
+	///
+	bool getStatus(Cursor &, FuncRequest const &, FuncStatus &) const;
+protected:
+	///
+	virtual void doDispatch(Cursor & cur, FuncRequest & cmd);
 private:
 	virtual Inset * clone() const;
 	///
-	int space_;
+	bool isNegative() const;
 	///
-	Dimension dim_;
+	int space_;
+	/// amount of space for \\hspace
+	Length length_;
 };
 
 
diff --git a/src/mathed/MathFactory.cpp b/src/mathed/MathFactory.cpp
index 4c32281d83..84bc7d33b9 100644
--- a/src/mathed/MathFactory.cpp
+++ b/src/mathed/MathFactory.cpp
@@ -51,6 +51,7 @@
 #include "MathSupport.h"
 
 #include "insets/InsetCommand.h"
+#include "insets/InsetSpace.h"
 
 #include "support/debug.h"
 #include "support/docstream.h"
@@ -60,7 +61,9 @@
 
 #include "frontends/FontLoader.h"
 
+#include "Encoding.h"
 #include "LyX.h" // use_gui
+#include "OutputParams.h"
 
 using namespace std;
 using namespace lyx::support;
@@ -316,7 +319,7 @@ MathAtom createInsetMath(docstring const & s)
 		if (inset == "decoration")
 			return MathAtom(new InsetMathDecoration(l));
 		if (inset == "space")
-			return MathAtom(new InsetMathSpace(l->name));
+			return MathAtom(new InsetMathSpace(to_ascii(l->name), ""));
 		if (inset == "dots")
 			return MathAtom(new InsetMathDots(l));
 		if (inset == "mbox")
@@ -473,13 +476,28 @@ bool createInsetMath_fromDialogStr(docstring const & str, MathData & ar)
 	docstring name;
 	docstring body = split(str, name, ' ');
 
-	if (name != "ref" )
+	if (name == "ref") {
+		InsetCommandParams icp(REF_CODE);
+		// FIXME UNICODE
+		InsetCommand::string2params("ref", to_utf8(str), icp);
+		mathed_parse_cell(ar, icp.getCommand());
+	} else if (name == "mathspace") {
+		InsetSpaceParams isp(true);
+		InsetSpace::string2params(to_utf8(str), isp);
+		InsetSpace is(isp);
+		odocstringstream os;
+		Encoding const * const ascii = encodings.fromLyXName("ascii");
+		OutputParams op(ascii);
+		is.latex(os, op);
+		mathed_parse_cell(ar, os.str());
+		if (ar.size() == 2) {
+			// remove "{}"
+			if (ar[1].nucleus()->asBraceInset())
+				ar.pop_back();
+		}
+	} else
 		return false;
 
-	InsetCommandParams icp(REF_CODE);
-	// FIXME UNICODE
-	InsetCommand::string2params("ref", to_utf8(str), icp);
-	mathed_parse_cell(ar, icp.getCommand());
 	if (ar.size() != 1)
 		return false;
 
diff --git a/src/mathed/MathParser.cpp b/src/mathed/MathParser.cpp
index 223fd992ac..6c9e880587 100644
--- a/src/mathed/MathParser.cpp
+++ b/src/mathed/MathParser.cpp
@@ -54,6 +54,7 @@ following hack as starting point to write some macros:
 #include "InsetMathRef.h"
 #include "InsetMathRoot.h"
 #include "InsetMathScript.h"
+#include "InsetMathSpace.h"
 #include "InsetMathSplit.h"
 #include "InsetMathSqrt.h"
 #include "InsetMathTabular.h"
@@ -671,7 +672,7 @@ docstring Parser::parse_verbatim_option()
 				putback();
 				res += '{' + parse_verbatim_item() + '}';
 			} else
-				res += t.asString();
+				res += t.asInput();
 		}
 	}
 	return res;
@@ -690,7 +691,7 @@ docstring Parser::parse_verbatim_item()
 				res += '{' + parse_verbatim_item() + '}';
 			}
 			else
-				res += t.asString();
+				res += t.asInput();
 		}
 	}
 	return res;
@@ -1594,6 +1595,22 @@ bool Parser::parse1(InsetMathGrid & grid, unsigned flags,
 			parse(cell->back().nucleus()->cell(0), FLAG_ITEM, InsetMath::TEXT_MODE);
 		}
 
+		else if (t.cs() == "hspace" && nextToken().character() != '*') {
+			docstring const name = t.cs();
+			docstring const arg = parse_verbatim_item();
+			Length length;
+			if (isValidLength(to_utf8(arg), &length))
+				cell->push_back(MathAtom(new InsetMathSpace(length)));
+			else {
+				// Since the Length class cannot use length variables
+				// we must not create an InsetMathSpace.
+				cell->push_back(MathAtom(new MathMacro(name)));
+				MathData ar;
+				mathed_parse_cell(ar, '{' + arg + '}');
+				cell->append(ar);
+			}
+		}
+
 #if 0
 		else if (t.cs() == "infer") {
 			MathData ar;
diff --git a/status.16x b/status.16x
index 971075fd5e..f656241ce0 100644
--- a/status.16x
+++ b/status.16x
@@ -48,6 +48,7 @@ What's new
 
 * USER INTERFACE
 
+- Support for customized horizontal space in math/formulas (bug 2558).
 
 
 * WINDOWS INSTALLER