Nasty Png in Tbutton on Windows XP SP3 (XP mode Windows 7)

Question

I have try my app (dev on Windows 7) on the Windows XP Mode (SP3). And my Tbutton (and other) pictures related to TImageList are very awfull (rounded of black).Do you have an explanation ? Or a solution ?

Thanks a lot, Have a nice day !

EDIT :

@Ken The same EXE, compiled on Windows XP or Windows 7 with D2009 gives me the same result. No transparency on XP Mode SP3 (maybe it is a problem on the virtual machine, but it is strange) and transparency on Windows 7...

@Ken With Delphi 2010 same problem : Test file (source+Exe) : http://www.onkeysoft.com/Test.zip

@David : One with Facebook, and the other don't know why, i have just enter my name and email... I thought i was login but not... (This is the first time I use stackoverflow sorry for problems)

Answer 1

Answer :

Windows 7 Pro : No Problem Windows XP mode (SP3) (Win7Pro) : Problem !

And .... Windows XP SP3 on VirtualBox Emulation : No problem !

So the problem is on the windows XP Mode, and the problem is solved...

(Image here : http://i.stack.imgur.com/LwCtq.png)