Return when no selected element to ungroup

git-svn-id: http://svg-edit.googlecode.com/svn/trunk@2837 eee81c28-f429-11dd-99c0-75d572ba1ddd

editor/svgcanvas.js

@@ -7236,6 +7236,9 @@ var pushGroupProperties = this.pushGroupProperties = function(g, undoable) {
 // significant recalculations to apply group's transforms, etc to its children
 this.ungroupSelectedElement = function() {
 	var g = selectedElements[0];
+    if (!g) {
+        return;
+    }
 	if ($(g).data('gsvg') || $(g).data('symbol')) {
 		// Is svg, so actually convert to group
 		convertToGroup(g);