diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3c737c7ba2..7490545c1d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -117,7 +117,6 @@ LYX_OPTION(REQUIRE_SPELLCHECK "Abort if no spellchecker available" OFF ALL)
 LYX_OPTION(ASPELL           "Require aspell" OFF ALL)
 LYX_OPTION(ENCHANT          "Require Enchant" OFF ALL)
 LYX_OPTION(HUNSPELL         "Require Hunspell" OFF ALL)
-LYX_OPTION(DEVEL_VERSION    "Build developer version" OFF ALL)
 LYX_OPTION(RELEASE          "Build release version, build debug when disabled" OFF ALL)
 LYX_OPTION(DEBUG            "Enforce debug build"  OFF ALL)
 LYX_OPTION(NO_OPTIMIZE      "Don't use any optimization/debug flags"  OFF ALL)
diff --git a/INSTALL.cmake b/INSTALL.cmake
index ffe5866b00..4c8d4789f3 100644
--- a/INSTALL.cmake
+++ b/INSTALL.cmake
@@ -141,7 +141,6 @@ Build options
     -- LYX_ASPELL               = OFF    : Require aspell
     -- LYX_ENCHANT              = OFF    : Require Enchant
     -- LYX_HUNSPELL             = OFF    : Require Hunspell
-    -- LYX_DEVEL_VERSION        = OFF    : Build developer version
     -- LYX_RELEASE              = OFF    : Build release version, build debug when disabled
     -- LYX_PACKAGE_SUFFIX       = ON     : Use version suffix for packaging
     -- LYX_PCH                  = OFF    : Use precompiled headers
diff --git a/config/lyxinclude.m4 b/config/lyxinclude.m4
index b07bf38f24..ead704b166 100644
--- a/config/lyxinclude.m4
+++ b/config/lyxinclude.m4
@@ -33,7 +33,6 @@ AC_MSG_RESULT([$build_type])
 lyx_flags="$lyx_flags build=$build_type"
 case $build_type in
     development) lyx_devel_version=yes
-                 AC_DEFINE(DEVEL_VERSION, 1, [Define if you are building a development version of LyX])
 		 LYX_DATE="not released yet" ;;
     prerelease) lyx_prerelease=yes ;;
 esac
diff --git a/development/cmake/TODO.txt b/development/cmake/TODO.txt
index 45c1e0df84..32cf54b292 100644
--- a/development/cmake/TODO.txt
+++ b/development/cmake/TODO.txt
@@ -26,8 +26,6 @@ Bug fixing
 
 Documentation
   * Better documentation, variable naming, more automake-like
-  * what does LYX_DEVEL_VERSION do?
-  * What is the difference with LYX_RELEASE=OFF?
   * how do I specify whether I want debug informations (-g flag) for unix?
 
 
diff --git a/development/cmake/config.h.cmake b/development/cmake/config.h.cmake
index f0a504a81a..7fac0b00b5 100644
--- a/development/cmake/config.h.cmake
+++ b/development/cmake/config.h.cmake
@@ -24,12 +24,6 @@
 #endif
 
 
-#cmakedefine LYX_DEVEL_VERSION 1
-#if defined(LYX_DEVEL_VERSION)
-	#define DEVEL_VERSION 1
-#else
-	#undef DEVEL_VERSION
-#endif
 #cmakedefine PACKAGE "${PACKAGE}"
 #cmakedefine PACKAGE_VERSION "${PACKAGE_VERSION}"
 #define PACKAGE_STRING "LyX ${PACKAGE_VERSION}"
diff --git a/src/BufferView.cpp b/src/BufferView.cpp
index 19547ef564..d2215627cf 100644
--- a/src/BufferView.cpp
+++ b/src/BufferView.cpp
@@ -1391,7 +1391,7 @@ void BufferView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 		break;
 
 	case LFUN_FONT_STATE:
-		dr.setMessage(cur.currentState());
+		dr.setMessage(cur.currentState(false));
 		break;
 
 	case LFUN_BOOKMARK_SAVE:
diff --git a/src/Cursor.cpp b/src/Cursor.cpp
index 0c8ee1d6c5..a139a2b310 100644
--- a/src/Cursor.cpp
+++ b/src/Cursor.cpp
@@ -1057,7 +1057,7 @@ void Cursor::updateTextTargetOffset()
 }
 
 
-void Cursor::info(odocstream & os) const
+void Cursor::info(odocstream & os, bool devel_mode) const
 {
 	for (int i = 1, n = depth(); i < n; ++i) {
 		operator[](i).inset().infoize(os);
@@ -1069,6 +1069,14 @@ void Cursor::info(odocstream & os) const
 		if (inset)
 			prevInset()->infoize2(os);
 	}
+	if (devel_mode) {
+		InsetMath * math = inset().asInsetMath();
+		if (math)
+			os << _(", Inset: ") << math->id();
+		os << _(", Cell: ") << idx();
+		os << _(", Position: ") << pos();
+	}
+
 }
 
 
@@ -2106,23 +2114,16 @@ docstring Cursor::selectionAsString(bool with_label) const
 }
 
 
-docstring Cursor::currentState() const
+docstring Cursor::currentState(bool devel_mode) const
 {
 	if (inMathed()) {
 		odocstringstream os;
-		info(os);
-#ifdef DEVEL_VERSION
-		InsetMath * math = inset().asInsetMath();
-		if (math)
-			os << _(", Inset: ") << math->id();
-		os << _(", Cell: ") << idx();
-		os << _(", Position: ") << pos();
-#endif
+		info(os, devel_mode);
 		return os.str();
 	}
 
 	if (inTexted())
-		return text()->currentState(*this);
+		return text()->currentState(*this, devel_mode);
 
 	return docstring();
 }
diff --git a/src/Cursor.h b/src/Cursor.h
index d1e13f684e..5c675c493a 100644
--- a/src/Cursor.h
+++ b/src/Cursor.h
@@ -205,7 +205,7 @@ public:
 	///
 	docstring selectionAsString(bool with_label) const;
 	///
-	docstring currentState() const;
+	docstring currentState(bool devel_mode) const;
 
 	/// auto-correct mode
 	bool autocorrect() const { return autocorrect_; }
@@ -300,7 +300,7 @@ public:
 	/// access to owning BufferView
 	BufferView & bv() const;
 	/// get some interesting description of top position
-	void info(odocstream & os) const;
+	void info(odocstream & os, bool devel_mode) const;
 	/// are we in math mode (2), text mode (1) or unsure (0)?
 	int currentMode();
 	/// reset cursor bottom to the beginning of the top inset
diff --git a/src/FuncCode.h b/src/FuncCode.h
index 7949bce41a..92d5e35268 100644
--- a/src/FuncCode.h
+++ b/src/FuncCode.h
@@ -473,6 +473,7 @@ enum FuncCode
 	LFUN_BUFFER_ZOOM,               // daniel, 20161028
 	LFUN_TOOLBAR_MOVABLE,           // daniel, 20160712
 	LFUN_FONT_CROSSOUT,             // uwestoehr 20170404
+	LFUN_DEVEL_MODE_TOGGLE,         // lasgouttes 20170723
 	LFUN_LASTACTION                 // end of the table
 };
 
diff --git a/src/LyXAction.cpp b/src/LyXAction.cpp
index 56b810306e..6aaec92428 100644
--- a/src/LyXAction.cpp
+++ b/src/LyXAction.cpp
@@ -1395,6 +1395,19 @@ void LyXAction::init()
 		{ LFUN_DEPTH_INCREMENT, "depth-increment", Noop, Edit },
 
 
+/*!
+ * \var lyx::FuncCode lyx::LFUN_DEVEL_MODE_TOGGLE
+ * \li Action: toggle a mode where more information is given in UI
+ * \li Syntax: devel-mode-toggle
+ * \li Notion: in so called "devel" mode, the information given in the
+ *             status bar is more precise, and the help documents are
+ *             open in editing mode.
+ * \li Origin: lasgouttes, 23 Jul 2017
+ * \endvar
+ */
+		{ LFUN_DEVEL_MODE_TOGGLE, "devel-mode-toggle", NoBuffer, System },
+
+
 /*!
  * \var lyx::FuncCode lyx::LFUN_DIALOG_DISCONNECT_INSET
  * \li Action: Closes opened connection to opened inset.
diff --git a/src/Text.cpp b/src/Text.cpp
index 8cac506e56..e1c37faf3a 100644
--- a/src/Text.cpp
+++ b/src/Text.cpp
@@ -1896,7 +1896,7 @@ bool Text::read(Lexer & lex,
 
 
 // Returns the current font and depth as a message.
-docstring Text::currentState(Cursor const & cur) const
+docstring Text::currentState(Cursor const & cur, bool devel_mode) const
 {
 	LBUFERR(this == cur.text());
 	Buffer & buf = *cur.buffer();
@@ -1953,22 +1953,22 @@ docstring Text::currentState(Cursor const & cur) const
 		}
 	}
 
-#ifdef DEVEL_VERSION
-	os << _(", Inset: ") << &cur.inset();
-	os << _(", Paragraph: ") << cur.pit();
-	os << _(", Id: ") << par.id();
-	os << _(", Position: ") << cur.pos();
-	// FIXME: Why is the check for par.size() needed?
-	// We are called with cur.pos() == par.size() quite often.
-	if (!par.empty() && cur.pos() < par.size()) {
-		// Force output of code point, not character
-		size_t const c = par.getChar(cur.pos());
-		os << _(", Char: 0x") << hex << c;
+	if (devel_mode) {
+		os << _(", Inset: ") << &cur.inset();
+		os << _(", Paragraph: ") << cur.pit();
+		os << _(", Id: ") << par.id();
+		os << _(", Position: ") << cur.pos();
+		// FIXME: Why is the check for par.size() needed?
+		// We are called with cur.pos() == par.size() quite often.
+		if (!par.empty() && cur.pos() < par.size()) {
+			// Force output of code point, not character
+			size_t const c = par.getChar(cur.pos());
+			os << _(", Char: 0x") << hex << c;
+		}
+		os << _(", Boundary: ") << cur.boundary();
+//		Row & row = cur.textRow();
+//		os << bformat(_(", Row b:%1$d e:%2$d"), row.pos(), row.endpos());
 	}
-	os << _(", Boundary: ") << cur.boundary();
-//	Row & row = cur.textRow();
-//	os << bformat(_(", Row b:%1$d e:%2$d"), row.pos(), row.endpos());
-#endif
 	return os.str();
 }
 
diff --git a/src/Text.h b/src/Text.h
index fc602fcf97..046ca9d4c8 100644
--- a/src/Text.h
+++ b/src/Text.h
@@ -157,8 +157,8 @@ public:
 	/// read-write access to individual paragraph
 	Paragraph & getPar(pit_type pit) { return pars_[pit]; }
 	// Returns the current font and depth as a message.
-	/// FIXME: replace Cursor with DocIterator.
-	docstring currentState(Cursor const & cur) const;
+	// When \param devel_mode is true, add more precise information
+	docstring currentState(Cursor const & cur, bool devel_mode) const;
 
 	/** Find the word under \c from in the relative location
 	 *  defined by \c word_location.
diff --git a/src/frontends/qt4/GuiApplication.cpp b/src/frontends/qt4/GuiApplication.cpp
index c9320ec403..d6a219e75e 100644
--- a/src/frontends/qt4/GuiApplication.cpp
+++ b/src/frontends/qt4/GuiApplication.cpp
@@ -1727,13 +1727,8 @@ void GuiApplication::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 		current_view_->message(bformat(_("Opening help file %1$s..."),
 					       makeDisplayPath(fname.absFileName())));
 		Buffer * buf = current_view_->loadDocument(fname, false);
-
-#ifndef DEVEL_VERSION
 		if (buf)
-			buf->setReadonly(true);
-#else
-		(void) buf;
-#endif
+			buf->setReadonly(!current_view_->develMode());
 		break;
 	}
 
diff --git a/src/frontends/qt4/GuiCommandBuffer.cpp b/src/frontends/qt4/GuiCommandBuffer.cpp
index c13bdfe578..4d94d97738 100644
--- a/src/frontends/qt4/GuiCommandBuffer.cpp
+++ b/src/frontends/qt4/GuiCommandBuffer.cpp
@@ -295,12 +295,6 @@ string const GuiCommandBuffer::historyDown()
 }
 
 
-docstring const GuiCommandBuffer::getCurrentState() const
-{
-	return view_->currentBufferView()->cursor().currentState();
-}
-
-
 vector<string> const
 GuiCommandBuffer::completions(string const & prefix, string & new_prefix)
 {
diff --git a/src/frontends/qt4/GuiCommandBuffer.h b/src/frontends/qt4/GuiCommandBuffer.h
index 49ed9bf043..41b39d2644 100644
--- a/src/frontends/qt4/GuiCommandBuffer.h
+++ b/src/frontends/qt4/GuiCommandBuffer.h
@@ -65,9 +65,6 @@ private:
 	/// return the next history entry if any
 	std::string const historyDown();
 
-	/// return the font and depth in the active BufferView as a message.
-	docstring const getCurrentState() const;
-
 	/// open a listbox and show the contents of the list. When reversed
 	/// is true, the contents of the list is filled bottom-up.
 	void showList(std::vector<std::string> const & list,
diff --git a/src/frontends/qt4/GuiView.cpp b/src/frontends/qt4/GuiView.cpp
index a257bb7268..d2e3ed9f27 100644
--- a/src/frontends/qt4/GuiView.cpp
+++ b/src/frontends/qt4/GuiView.cpp
@@ -508,7 +508,7 @@ QSet<Buffer const *> GuiView::GuiViewPrivate::busyBuffers;
 
 GuiView::GuiView(int id)
 	: d(*new GuiViewPrivate(this)), id_(id), closing_(false), busy_(0),
-	  command_execute_(false), minibuffer_focus_(false)
+	  command_execute_(false), minibuffer_focus_(false), devel_mode_(false)
 {
 	connect(this, SIGNAL(bufferViewChanged()),
 	        this, SLOT(onBufferViewChanged()));
@@ -715,6 +715,7 @@ void GuiView::saveLayout() const
 {
 	QSettings settings;
 	settings.setValue("zoom", lyxrc.currentZoom);
+	settings.setValue("devel_mode", devel_mode_);
 	settings.beginGroup("views");
 	settings.beginGroup(QString::number(id_));
 #if defined(Q_WS_X11) || defined(QPA_XCB)
@@ -746,6 +747,7 @@ bool GuiView::restoreLayout()
 	QSettings settings;
 	lyxrc.currentZoom = settings.value("zoom", lyxrc.zoom).toInt();
 	lyx::dispatch(FuncRequest(LFUN_BUFFER_ZOOM, convert<docstring>(lyxrc.currentZoom)));
+	devel_mode_ = settings.value("devel_mode", devel_mode_).toBool();
 	settings.beginGroup("views");
 	settings.beginGroup(QString::number(id_));
 	QString const icon_key = "icon_size";
@@ -1254,7 +1256,7 @@ void GuiView::showMessage()
 	if (msg.isEmpty()) {
 		BufferView const * bv = currentBufferView();
 		if (bv)
-			msg = toqstr(bv->cursor().currentState());
+			msg = toqstr(bv->cursor().currentState(devel_mode_));
 		else
 			msg = qt_("Welcome to LyX!");
 	}
@@ -1900,6 +1902,10 @@ bool GuiView::getStatus(FuncRequest const & cmd, FuncStatus & flag)
 		enable = d.tabWorkAreaCount() > 1;
 		break;
 
+	case LFUN_DEVEL_MODE_TOGGLE:
+		flag.setOnOff(devel_mode_);
+		break;
+
 	case LFUN_TOOLBAR_TOGGLE: {
 		string const name = cmd.getArg(0);
 		if (GuiToolbar * t = toolbar(name))
@@ -3861,6 +3867,14 @@ void GuiView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 			closeBufferAll();
 			break;
 
+		case LFUN_DEVEL_MODE_TOGGLE:
+			devel_mode_ = !devel_mode_;
+			if (devel_mode_)
+				dr.setMessage(_("Developer mode is now enabled."));
+			else
+				dr.setMessage(_("Developer mode is now disabled."));
+			break;
+
 		case LFUN_TOOLBAR_TOGGLE: {
 			string const name = cmd.getArg(0);
 			if (GuiToolbar * t = toolbar(name))
diff --git a/src/frontends/qt4/GuiView.h b/src/frontends/qt4/GuiView.h
index a3158a42f3..998fcc255b 100644
--- a/src/frontends/qt4/GuiView.h
+++ b/src/frontends/qt4/GuiView.h
@@ -343,6 +343,8 @@ public:
 	void hideDialog(std::string const & name, Inset * inset);
 	///
 	void disconnectDialog(std::string const & name);
+	///
+	bool develMode() const { return devel_mode_; }
 
 private:
 	/// Saves the layout and geometry of the window
@@ -469,6 +471,9 @@ private:
 
 	// movability flag of all toolbars
 	bool toolbarsMovable_;
+
+	// developer mode
+	bool devel_mode_;
 };
 
 } // namespace frontend
diff --git a/src/frontends/qt4/GuiViewSource.cpp b/src/frontends/qt4/GuiViewSource.cpp
index d58e173837..80d3c0b459 100644
--- a/src/frontends/qt4/GuiViewSource.cpp
+++ b/src/frontends/qt4/GuiViewSource.cpp
@@ -197,20 +197,21 @@ void ViewSourceWidget::updateView(BufferView const * bv)
 	           masterPerspectiveCB->isChecked());
 	QString old = document_->toPlainText();
 	QString qcontent = toqstr(content);
-#ifdef DEVEL_VERSION
-	// output tex<->row correspondences in the source panel if the "-dbg latex"
-	// option is given.
-	if (texrow_ && lyx::lyxerr.debugging(Debug::LATEX)) {
-		QStringList list = qcontent.split(QChar('\n'));
-		docstring_list dlist;
-		for (QStringList::const_iterator it = list.begin(); it != list.end(); ++it)
-			dlist.push_back(from_utf8(fromqstr(*it)));
-		texrow_->prepend(dlist);
-		qcontent.clear();
-		for (docstring_list::iterator it = dlist.begin(); it != dlist.end(); ++it)
-			qcontent += toqstr(*it) + '\n';
+	if (guiApp->currentView()->develMode()) {
+		// output tex<->row correspondences in the source panel if the "-dbg latex"
+		// option is given.
+		if (texrow_ && lyx::lyxerr.debugging(Debug::LATEX)) {
+			QStringList list = qcontent.split(QChar('\n'));
+			docstring_list dlist;
+			for (QStringList::const_iterator it = list.begin(); it != list.end(); ++it)
+				dlist.push_back(from_utf8(fromqstr(*it)));
+			texrow_->prepend(dlist);
+			qcontent.clear();
+			for (docstring_list::iterator it = dlist.begin(); it != dlist.end(); ++it)
+				qcontent += toqstr(*it) + '\n';
+		}
 	}
-#endif
+
 	// prevent gotoCursor()
 	QSignalBlocker blocker(viewSourceTV);
 	bool const changed = setText(qcontent);
diff --git a/src/mathed/InsetMathHull.cpp b/src/mathed/InsetMathHull.cpp
index 01501929c6..67c59ddede 100644
--- a/src/mathed/InsetMathHull.cpp
+++ b/src/mathed/InsetMathHull.cpp
@@ -2248,7 +2248,7 @@ void InsetMathHull::revealCodes(Cursor & cur) const
 	if (!cur.inMathed())
 		return;
 	odocstringstream os;
-	cur.info(os);
+	cur.info(os, false);
 	cur.message(os.str());
 /*
 	// write something to the minibuffer