Tk Source Code

Sometimes, yet to be determined, grabbing the sizegrip MOVES (instead of resizes) the window. The window is shifted by 10 pixels or so to the bottom of the screen.
The sizegrip is packed to the right of an expanded frame packed to the bottom of the toplevel.

Serhiy, many thanks! Merged into main, core-9-0-branch, and core-8-6-branch by commits [a0496a58], [6873ef21], and [2067f3d7].

Reproduced on X11 with metacity, mutter/gnome-shell and KWin, even without the sizegrip: wm geometry . 400x300 moves the window. It moves by (-22,-14) under metacity, (-14,-12) under gnome-shell and 42 pixels down under KWin (Xwayland). It does not move without a window manager, or under fvwm, openbox, xfwm4, icewm or compiz 0.9. Windows is not affected.

The cause is in Tk: a size-only geometry still sends back the position that Tk recorded from the window manager's frame, and these window managers interpret it differently. ttk::sizegrip made this worse by always passing the position with the new size. That was added for [2912356] as a workaround for compiz, but the underlying cause was the same.

Proposed fix in branch wm-geometry-size-only: only send the position when one is specified, and let the sizegrip set only the size. Test wm-geometry-2.2 fails on trunk under metacity, gnome-shell and KWin and passes with the fix.

More information needed: what platform, and, if X11, what window manager?  If you can narrow down the circumstances under which this occurs that would be helpful as well.

(I'll note however that it's unlikely this problem will be fixable.   Most likely cause of the problem is ICCCM noncompliance in Tk and/or the window manager.)