Importing new media creates a hidden dialog box

I will switch things up. For me, the issue is new. I've used Premiere for about a dozen years. My computer is new. Since July. The issue just presented itself with this project. 

I've hoped that they would have changed Premiere's monitor use but they haven't. So we need to work within what it does do.

And that is ... if the main Premiere windew, with the app's top menu bar, is not on the 'main' UI screen it gets cranky. It also gets cranky if the Program monitor isn't on the main UI screen.

I have numerous saved workspaces. So I always keep the 'main' window on that screen, with ECP panel and timeline and Program monitor, typically with scopes or audio panel also ... and created a panel group on my second screen that has the Production, Projects, and Effects typically. Transmit Out goes to my 3rd monitor for a full-screen clean feed look.

I do have two monitors. Both 4k. The monitor the OS regards as number 1 is what I use as the external, to view the project output full screen. Number 2 is where the timeline (the program) resides. 

I believe I can change that.

You have two monitors, right?

Which is your main OS monitor, and does the 'main' window of Premiere (with the top menu bar) appear on that monitor? Do you have the Program monitor on the 'main' UI window screen, or did you move that to the second monitor?

I am not able to see the dialog box. I've tried up down left right arrows.  I've tried Tab. I've tried ESC. I've tried Windows Key and various other keys.  I can't make the box appear on either of the monitors.  At that point all I can do is use the task manager to kill the application and open it again.

I've also deleted the preferences file and forced a new one but that had no impact either.

Also...what does that dialog box, actually say?