Possible bug deleting images with standalone viewer

I had this in several versions.
When deleting images with the standalone viewer, every few images the viewer jumps to the background (or Dopus jumps to the foreground). I have the viewer maximized, not fullscreen.
Is this a bug?

I used to see that every so often a very long time ago. I don't think I have seen it in recent versions, though.

Increasing the delay for Preferences / File Operations / Progress Indicators / Delayed progress indicators may help, perhaps.

Doubled the value (from 800ms to 1600ms)... didn't help though...
I haven't restarted Dopus yet, so maybe the new value hasn't been processed yet.

Here's what I am using, FWIW:

I copied your settings, it still happens though.
I also restarted Dopus this time but the view still jumps to the background every few images or so (sometimes after two but other times after five or six).

Is the viewer "on top"? That may be a factor. For me it's not:

It wasn't for me either but now I set it to Opus Only and that seems to do the trick...