SUMMARY
If you have a display configuration where one display is above/below, Spectacle will not move the Resolution Preview box below the selection, even if the selection box is not visible on the upper display. If you have the upper/lower display arranged with an offset, such as more to the left/right and not directly aligned, then the preview will appear partially on the upper display even if it is not all visible on the upper display.

If you have a setup where the upper/lower display is entirely offset, such as only touching at the corners, there is nowhere for the resolution preview box to be visible, but Spectacle will still draw it, although there is nowhere to see it.

You can tell it is drawing it because if the resolution preview box moves from top to bottom, it will fade in/fade out, but no such animation plays.


STEPS TO REPRODUCE
1. Activate Spectacle Rectangle Select on a display configuration as described above.
2. Draw a selection box at the top of the top display, or at a part on the bottom display where there is an offset such that content above this display will not draw on the upper display.
3. The Resolution Preview box is not visible.

OBSERVED RESULT
Spectacle Resolution Preview will not draw below the region select on multi-screen configurations with at least one vertical display. 


EXPECTED RESULT
Spectacle Resolution Preview should always draw above/below itself if it is at the top/bottom of a display with no display above it to render on.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.7.8 Linux Zen
KDE Plasma Version: 6.0.1
KDE Frameworks Version:  6.0.0
Qt Version: 6.6.2