Dual monitor bug with popup windows disappearing

[RBBOT]

I'm using dual monitors with my desktop extended across both, and I have found the following issue in version 5.2.0:

1. Open Textpad on the left monitor
2. Click Find in Files on the toolbar
3. For some reason, this dialog opens on the right edge of the right screen
4. Close Find in Files dialog
5. Move the main Textpad window to the right monitor
6. Click Find in Files again

This time the find in files dialog opens off-screen and I can't find a way to get it back without closing Textpad and starting afresh, even if you move the main window back to the original monitor.

It's not restricted to this one pop-up. The same bug occurs with the replace dialog if you start off with the main window on the right monitor and move it to the left monitor in step 5.