Felix Palmen 
@thomasadam just had an idea myself: #XPresent would be needed for vsync, but maybe this isn't even the problem and just keeping an offscreen pixmap for the window would already be enough ... ๐ค
Next step completed, my #TextBox widget now supports mouse input: click, doubleclick and drag ๐ฅณ.
Not so nice: With overall more drawing operations, I see #flicker happening more often ๐. Did some research already, it seems with #XRender, the only way to avoid it would be to render to some #pixmap (instead of the window directly) and use #XPresent to get it on the screen? @thomasadam do you know an "easier" way? ๐