sculpt: unexpected action on windows without maximize option

[tomga]

For windows which can be resized themed_decorator paints a square in left part of window title bar.

For windows that cannot be resized (like top_view or msr_gui) this indicator is not painted, however it seems that action of maximization is still active when clicking in this area (window is moved to upper left corner of the screen and next click restores previous position).

It is a minor issue and I report it because I believe it may have not been spotted.