Window shrinks or expands unexpectedly when resizing using the mouse

[bakkeby]

This can happen if you have changed the transformation matrix for your mouse using xinput, e.g.

xinput --set-prop 'pointer:Logitech MX Master 2S' 'Coordinate Transformation Matrix' 2.4 0 0 0 2.4 0 0 0 1

Three known solutions for this issue:

1) reset the transformation matrix back to default or

2) use an /etc/X11/xorg.conf.d/50-mouse-acceleration.conf file containing

Section "InputClass"
        Identifier "g403"
        Driver "libinput"
        MatchIsPointer "yes"
        Option "AccelProfile" "flat"
        Option "AccelSpeed" "0.3"
EndSection

When AccelProfile is flat then AccelSpeed controls mouse sensitivity instead of acceleration. If this value is equivalent to your xinput sensitivity then this issue should go away [ref].

3) use the resizepoint patch
The issue with the client expanding or shrinking unexpectedly has to do with warping the cursor to the bottom right corner (or any corner if the resizecorners patch is used) and mouse acceleration seemingly causes issues with calculating the distance between the warped mouse pointer and the client's opposite corner.

The resizepoint patch allows windows to be resized from the point you clicked, hence it does not warp the cursor and thus should not have this issue.