fixed: undo support for fontpanel

AppKit/CPTextView/CPTextView.j

@@ -1479,6 +1479,12 @@ var kDelegateRespondsTo_textShouldBeginEditing
         [_textStorage setFont:_font];
     }
 
+    var currentAttributes = [_textStorage attributesAtIndex:range.location effectiveRange:nil] || _typingAttributes;
+
+    [[[[self window] undoManager] prepareWithInvocationTarget:self]
+                                                      setFont:[currentAttributes objectForKey:CPFontAttributeName] || _font
+                                                        range:CPMakeRangeCopy(range)];
+
     [_textStorage addAttribute:CPFontAttributeName value:font range:CPMakeRangeCopy(range)];
     [_layoutManager _validateLayoutAndGlyphs];
 }
@@ -1488,7 +1494,10 @@ var kDelegateRespondsTo_textShouldBeginEditing
     var currRange = CPMakeRange(_selectionRange.location, 0),
         oldFont,
         attributes,
-        scrollRange = CPMakeRange(CPMaxRange(_selectionRange), 0);
+        scrollRange = CPMakeRange(CPMaxRange(_selectionRange), 0),
+        undoManager = [[self window] undoManager];
+
+    [undoManager beginUndoGrouping];
 
     if ([self isRichText])
     {
@@ -1518,6 +1527,8 @@ var kDelegateRespondsTo_textShouldBeginEditing
         scrollRange = CPMakeRange(length, 0);
     }
 
+    [undoManager endUndoGrouping];
+
     [_layoutManager _validateLayoutAndGlyphs];
     [self sizeToFit];
     [self setNeedsDisplay:YES];