backport rev. 23610:

URL: http://www.lyx.org/trac/changeset/23610
Log:
* fix for http://bugzilla.lyx.org/show_bug.cgi?id=2556
  "not possible to delete a label of a formula":

  Press forward delete at the end of a row and the label is deleted.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/branches/BRANCH_1_5_X@23685 a592a061-630c-0410-9148-cb99ea01b6c8

src/mathed/InsetMathHull.cpp

@@ -29,6 +29,7 @@
 #include "Text.h"
 
 #include "Buffer.h"
+#include "buffer_funcs.h"
 #include "BufferParams.h"
 #include "BufferView.h"
 #include "CutAndPaste.h"
@@ -442,7 +443,11 @@ docstring InsetMathHull::label(row_type row) const
 void InsetMathHull::label(row_type row, docstring const & label)
 {
 	//lyxerr << "setting label '" << label << "' for row " << row << endl;
-	label_[row] = label;
+	if (label.empty()) {
+		nonum_[row] = true;
+		label_[row].clear();
+	} else
+		label_[row] = label;
 }
 
 
@@ -1119,6 +1124,19 @@ void InsetMathHull::doDispatch(Cursor & cur, FuncRequest & cmd)
 		break;
 	}
 
+	case LFUN_WORD_DELETE_FORWARD:
+	case LFUN_CHAR_DELETE_FORWARD:
+		if (col(cur.idx()) + 1 == ncols()
+		    && cur.pos() == cur.lastpos()
+		    && !label(row(cur.idx())).empty()) {
+			recordUndoInset(cur);
+			label(row(cur.idx()), docstring());
+		} else {
+			InsetMathGrid::doDispatch(cur, cmd);
+			return;
+		}
+		break;
+
 	case LFUN_INSET_INSERT: {
 		//lyxerr << "arg: " << to_utf8(cmd.argument()) << endl;
 		std::string const name = cmd.getArg(0);

status.15x

@@ -80,6 +80,8 @@ What's new
 
 * USER INTERFACE:
 
+- Allow deleting a label in a formula with the delete key (bug 2556).
+
 - Allow to enter starred math commands such as \tag* (bug 4584).
 
 - Load amsmath when \tag or \tag* is used (bug 4586).