diff --git a/lib/layouts/stdinsets.inc b/lib/layouts/stdinsets.inc
index fab6282d85..cfb0804f9d 100644
--- a/lib/layouts/stdinsets.inc
+++ b/lib/layouts/stdinsets.inc
@@ -285,7 +285,7 @@ InsetLayout URL
 	HTMLIsBlock           false
 End
 
-InsetLayout OptArg
+InsetLayout Argument
 	LabelString           opt
 	LabelFont
 	  Color               collapsable
diff --git a/lib/lyx2lyx/lyx_2_0.py b/lib/lyx2lyx/lyx_2_0.py
index fd815b3bcd..5b962e5128 100644
--- a/lib/lyx2lyx/lyx_2_0.py
+++ b/lib/lyx2lyx/lyx_2_0.py
@@ -1481,8 +1481,8 @@ def revert_lyx_version(document):
         import lyx2lyx_version
         version = lyx2lyx_version.version
     except:
-   	    pass
-	
+        pass
+
     i = 0
     while 1:
         i = find_token(document.body, '\\begin_inset Info', i)
@@ -1697,6 +1697,27 @@ def revert_align_decimal(document):
     document.body[l].replace('decimal', 'center')
 
 
+def convert_optarg(document):
+  " Convert \\begin_inset OptArg to \\begin_inset Argument "
+  i = 0
+  while 1:
+    i = find_token(document.body, '\\begin_inset OptArg', i)
+    if i == -1:
+      return
+    document.body[i] = "\\begin_inset Argument"
+    i += 1
+
+
+def revert_argument(document):
+  " Convert \\begin_inset Argument to \\begin_inset OptArg "
+  i = 0
+  while 1:
+    i = find_token(document.body, '\\begin_inset Argument', i)
+    if i == -1:
+      return
+      document.body[i] = "\\begin_inset OptArg"
+      i += 1
+      
 ##
 # Conversion hub
 #
@@ -1748,10 +1769,12 @@ convert = [[346, []],
            [389, [convert_html_quotes]],
            [390, []],
            [391, []],
-           [392, [convert_beamer_args]]
+           [392, [convert_beamer_args]],
+           [393, [convert_optarg]]
           ]
 
-revert =  [[391, [revert_beamer_args]],
+revert =  [[392, [revert_argument]],
+           [391, [revert_beamer_args]],
            [390, [revert_align_decimal]],
            [389, [revert_output_sync]],
            [388, [revert_html_quotes]],
diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index c4e457b8b6..fcbf23e24d 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -126,7 +126,7 @@ namespace {
 
 // Do not remove the comment below, so we get merge conflict in
 // independent branches. Instead add your own.
-int const LYX_FORMAT = 392; // rgh: beamer layout change
+int const LYX_FORMAT = 393; // rgh: rename OptArg to Argument in LyX format
 
 typedef map<string, bool> DepClean;
 typedef map<docstring, pair<InsetLabel const *, Buffer::References> > RefCache;
diff --git a/src/factory.cpp b/src/factory.cpp
index 4701f9a9ab..9f39a2d229 100644
--- a/src/factory.cpp
+++ b/src/factory.cpp
@@ -562,7 +562,7 @@ Inset * readInset(Lexer & lex, Buffer * buf)
 			inset.reset(new InsetNewpage);
 		} else if (tmptok == "Newline") {
 			inset.reset(new InsetNewline);
-		} else if (tmptok == "OptArg") {
+		} else if (tmptok == "Argument") {
 			inset.reset(new InsetArgument(buf));
 		} else if (tmptok == "Float") {
 			inset.reset(new InsetFloat(buf, string()));
diff --git a/src/insets/InsetArgument.cpp b/src/insets/InsetArgument.cpp
index 67e48b126f..55a97f3e5f 100644
--- a/src/insets/InsetArgument.cpp
+++ b/src/insets/InsetArgument.cpp
@@ -28,7 +28,7 @@ InsetArgument::InsetArgument(Buffer * buf)
 
 void InsetArgument::write(ostream & os) const
 {
-	os << "OptArg" << "\n";
+	os << "Argument" << "\n";
 	InsetCollapsable::write(os);
 }
 
diff --git a/src/insets/InsetArgument.h b/src/insets/InsetArgument.h
index 46157bd745..43000f9bc4 100644
--- a/src/insets/InsetArgument.h
+++ b/src/insets/InsetArgument.h
@@ -39,7 +39,7 @@ private:
 	/// code of the inset
 	InsetCode lyxCode() const { return ARG_CODE; }
 	///
-	docstring name() const { return from_ascii("OptArg"); }
+	docstring name() const { return from_ascii("Argument"); }
 	/// Standard LaTeX output -- short-circuited
 	int latex(odocstream &, OutputParams const &) const;
 	/// Standard plain text output -- short-circuited