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

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 :开发者_如何学JAVA 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 :

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)

Have you checked if the option Enable Runtime Themes is enabled from Project menu > Options > application.

also try to set the DrawingSytle property of the ImageList to dsTransparent

By default, windows 7 XP mode emulation runs in 16 bits color mode. Historically, Delphi PNG transparency support hasn't been too happy with color depths other than 32 bits.

Try to run the same application on a real XP machine with the display set to 16 bits, and I'd expect you to encounter the exact same issues.