Ephox window view losing focus

I’ve just heard of an odd problem that some of my users are having. I can’t recreate the problem myself.

They might be typing in the separate window view of an Ephox control and it disappears and they’re looking at another browser tab. Then they go back to the window again, do a bit more work and it switches again. It’s been reported in both Internet Explorer and Chrome. Ephox version is

Has anyone else seen this?