i think all that is necessary is a correction of the y-coordinates to reach the upper part of the window.

Yes i know, i wrote it here already (the right window), but it would be nice if the left MB (the left Window) would also centered, because i use it to transfer items between storages.

What's the problem to open it with any character using "one-click RMB"? It will always open on center.

So it isn't possible to close or move it directly.

Looks like wrong XY-reference.