So I am having the issue where the UI is not staying put.
I think that it may be something with my IsBoxer set up (Below) and interaction with ImGUI.
But I am not familiar enough with the ImGUI windowing to understanding the interaction between It and the IS boxer regions.
Steps to Recreate.
1) /invisdisplay unlock
2) position the invisdisplay window where I want it to be (Main toon in region 1)
3) /invisdisplay lock (happens with or without lock actually)
4) Switch toon (Any toon in region 3-7)
This puts my main toon in region 2
5) Switch back to main toon
Puts Main toon back into region 1
Invis display window is moved.
After playing around with it to me it seems that there is some odd bounds checking that is moving the invisdisplay window.
As long as I keep the top left of the invisdisplay in the red bounded region in the image the UI stays put.
If I the invisdisplay window outside of the red bounds the location of the window is adjusted so that the top left is within the red bounds.
I realize this is probably less about the script and more about IsBoxer/ImGUI interaction but since someone else posted a similar issue (2022) Id add this here, also this is the only thing I use that this happens to.

Active region 1
Reset region 1