[Lazarus] Canvas font transparent background

[Leonardo M. Ramé]

Hi, I'm writing text to a TPaintBoxs's canvas and I'm getting different
output on Windows than Linux.

In Linux, the baground of text is transparent, this is the expected
behavior. In Windows, there's a black box below the text.

Should I set Pen, Brush or Font with some property to setup transparency
in Canvas fonts?

Thanks in advance,
-- 
Leonardo M. Ramé
http://leonardorame.blogspot.com