Hello Bentley,
This has been a persistent issue for the entire time I have been a Bentley CAD user.
Losing dialog boxes still seems so easy to do, yet difficult to recover/restore.
One example is that if I move a dialog outside of the application window, then move the application window to another monitor, the dialog does not follow it.
It gets worse, if for example, a dialog box is minimised, and then the application window is moved, even within the same monitor, the dialog loses association.
This is a long-standing bug that I hope can be made a bit more coherent instead of requiring the UPF be replaced, or some keyboard-mouse yoga tricks to try and move the dialog back to the application window.
If dialog boxes can have forced association property with a parent app window to stay within that boundary, and be parent app window 'aware'? Even if the application window is minimised to just the title bar, the dialog remembers/has properties forcing it to remain attached and restore it windin the application boundary when the application window is restored?
You can try this:
https://communities.bentley.com/products/microstation/w/microstation__wiki/15820/dialog-box-cannot-be-moved-or-located