Default LAF decorated frame does not support transparent icons

When I set a transparent image (say INT_ARGB) as the icon of a defaultLAF decorated JFrame, the icon does not appear transparent. I expect to see the background (color of the ocean theme) through the transparent portions of the image but I see a white background.

I have attached 2 screenshots of how they look on native title bar and swing's title bar. This is noticed on all platforms atleast since 1.5. All native decorations support transparent icons by default and would be good if Swing's title bar also supports it.

I have attached a sample test and a transparent image. Run the application. Click on the 'SetIconImage' button and check the icon. If you see a white background around the image, the bug is reproduced.