Fix bug 3407: Undo with text-in-mathmode

http://bugzilla.lyx.org/show_bug.cgi?id=3407

	* InsetMathNest.cpp (doDispatch/LFUN_MATH_MODE): handle undo



git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/branches/BRANCH_1_5_X@26187 a592a061-630c-0410-9148-cb99ea01b6c8

src/mathed/InsetMathNest.cpp

@@ -917,6 +917,7 @@ goto_char_backwards:
 		// ignore math-mode on when already in math mode
 		if (currentMode() == Inset::MATH_MODE && cmd.argument() == "on")
 			break;
+		recordUndoSelection(cur);
 		cur.macroModeClose();
 		docstring const save_selection = grabAndEraseSelection(cur);
 		selClearOrDel(cur);
@@ -927,6 +928,7 @@ goto_char_backwards:
 		cur.niceInsert(save_selection);
 #else
 		if (currentMode() == Inset::TEXT_MODE) {
+			recordUndoSelection(cur);
 			cur.niceInsert(MathAtom(new InsetMathHull("simple")));
 			cur.message(_("create new math text environment ($...$)"));
 		} else {

status.15x

@@ -62,6 +62,7 @@ What's new
 - Empty lines are correctly removed when the cursor moves due to the
   "cursor follows scrollbar" feature (bug 5065).
 
+- Fix undo for "text in math mode" (bug 3407).
 
 * DOCUMENTATION AND LOCALIZATION