Thanks for writing in.
You may have to edit your workspace a bit. All the panels in the screenshot are not in a panel group. The thick divider line shows that the panels are not in the same group. Move the panels in the same group.
Hope it helps.
How to find out the panels in the same group?
I don't know about that. The screen shot makes it a bit hard to tell, but for Stacked mode (which is where solo works) the panels appear to be in the right configuration.
I think you should reset the default workspace.
I have AE 2022 on Mac, and my solo mode enable/disable works. So it is a feature of 2022, at least on MAC.
The panels appear to be in the right configuration (stacked mode) for the solo command to work.
When I renable solo, I right–click on the panel name and choose the solo option and then all the other open panels close.
It might be a glitch,
you can try resetting the workspace Window > Workspace > Reset "Default" to Saved Workspace, or you could try resetting your preferences.
After resetting "Default" workspace I got a result like this
When "Review" panel is active I got desired format in RHS.
Your original screenshot is showing that you dragged some panels around. You can change the workspace, as you figured out above, but to keep your custom one and get the solo option working again, just drag one panel's tab onto another one to bring them back into a group. This has nothign to do with AE 2020 vs 2022, the behavior is exactly the same in both versions.
Thanks for the help.