I had reported a bug here but then discovered i cannot reproduce it and reported that i had mistaken.
Recently i started using GridMove after a period of inactivity and discovered that the bug persists. I investigated it and here's the result.
When started, GridMove does respect docked windows. But if you undock a window and dock it back, GridMove will no longer respect it: when placing windows on grid, it would place them behind the docked window.
To resolve the issue, i have to restart GridMove every time i drag a dockable window.
This is definitely a bug. Please say you're gonna fix it.