SyntaxBomb - Indie Coders

Whilst looking into the MaxGUI module, I tried the provided example (samples/maxgui/imagedrop.bmx) to get some ideas.

However this does not work (for me) if the window is created with the resizeable flag as per example, only if I remove this flag does it work.

Is this a bug (generally/Linux) or a "feature" only available in Windows or MacOS?