I am using Photolab 4.2.1 on a MacBook Pro with an Apple M1 processor, running MacOS Big Sur. I have the problem that the image browser has disappeared.
More specifically, when I undock the image browser, I can view it. But when I dock the image browser, it does not appear at the bottom of the application screen or anywhere else.
I have tried different screen resolutions as well as external monitors and they made no difference.
The problem does not occur with DXO Photolab 2 running on the same machine. It also does not occur with DXO Photolab 4 running on my Intel-based Mac Pro.