@dibo
I've updated Assign function so now it should take transparency into account.
I don't understand why this error pops up. I tested BGRA drawing on forms and it was working fine. Does the bgrafunctest work on your configuration ?
Maybe you are using BGRADefaultBitmap unit instead of BGRABitmap unit. It should not use DataDrawOpaque of TBGRADefaultBitmap but DrawOpaque from TBGRAGtkBitmap instead.
But you are using TBGRABitmap that should redirect to the right implementation. So maybe is there a problem with the $IFDEF.
@indianajones
There was a problem of font size, it's fixed. Every form must have a font size set to avoid it to change according to system configuration. If font size is zero, then it's kind of random.
About BorderStyle, here on Windows, if I set to Single border, the form becomes sizable.
I don't understand why you have the size thing at the bottom right, because Dialog border should not be sizable. By the way, what does Single border mean exactly for a form ?