<Swing Dev> [9] Review request for 8027639: JComboBox's popup leaves tracks after closing

[Sergey Bylokhov]

On 25.10.16 14:42, Alexandr Scherbatiy wrote:
>> When the Swing repaint manager paints Swing to a separate off-screen
>> buffer the root window is not painted. So in case of non-opaque root
>> window having transparent background the repainted buffer area
>> transparency is not restored and previously visible Swing components
>> can remain visible.
>>
>> The solution is to paint the root window's background to the repainted
>> area in case the root window is non-opaque.
>   Should the previous composite be restored after the rect filling?

Did you check that if the rootpane background contain non-zero alpha it 
does not draws twice? The first one when the the root will be draw 
itself and the second time in the new code when the component will be 
drawn? probably backbuffer should be initialized to Color(0,0,0,0) instead?


-- 
Best regards, Sergey.