Compositor issue: if you open a small screen you can move the workbench screen above the X11 limits

[mattrust]

Describe the bug
On hosted if you run a program which opens a small screen you can move the workbench screen above the top limit of the X11 window.

To Reproduce
Steps to reproduce the behavior:

1. Open a Shell and run the program SYS:Developer/Debug/Tests/intuition/smallscreen
2. Drag the created screen downwards
3. Drag the workbench screen upwards
4. After releasing the mouse you can't reach the workbench screen's title bar anymore. After closing the small screen the workbench screen jumps back but there is an offset between mouse pointer and active point.

Expected behaviour
It shouldn't be possible the move a screen upwards so that you can't reach the title bar anymore.

Screenshots

Architecture

• linux (hosted)

Not yet tested

• Amiga (including UAE, Vampire cards)
• pc (native)
• Raspberry Pi
• mingw
• darwin
• other:

CPU

• x86_64

Not yet tested

• i386
• m68k
• arm
• ppc
• other:

Version
Provide the Git ID from AboutAROS (call menu Wanderer>AROS>About)

Additional context
Add any other context about the problem here.

[mattrust]

Problem still exists on 2022-07-07.