Reimplemented setImageDimsWhenDisabled: on CPButton to only dim the image instead of the entire button

AppKit/_CPImageAndTextView.j

@@ -63,6 +63,7 @@ var HORIZONTAL_MARGIN   = 3.0,
     
     CPCellImagePosition     _imagePosition;
     CPImageScaling          _imageScaling;
+    BOOL                    _shouldDimImage;
     
     CPImage                 _image;
     CPString                _text;
@@ -211,6 +212,17 @@ var HORIZONTAL_MARGIN   = 3.0,
     return _imageScaling;
 }
 
+- (void)setDimsImage:(BOOL)shouldDim
+{
+    var shouldDimImage = !!shouldDimImage;
+
+    if (_shouldDimImage !== shouldDimImage)
+    {
+        _shouldDimImage = shouldDim;
+        [self setNeedsLayout];
+    }
+}
+
 - (void)setTextColor:(CPColor)aTextColor
 {
     if (_textColor === aTextColor)
@@ -572,6 +584,11 @@ var HORIZONTAL_MARGIN   = 3.0,
             imageHeight *= scale;
         }
 
+        if (CPFeatureIsCompatible(CPOpacityRequiresFilterFeature))
+            imageStyle.filter = @"alpha(opacity=" + _shouldDimImage ? 35 : 100 + ")";
+        else
+            imageStyle.opacity = _shouldDimImage ? 0.35 : 1.0;
+
         _DOMImageElement.width = imageWidth;
         _DOMImageElement.height = imageHeight;        
         imageStyle.width = MAX(imageWidth, 0) + "px";