Looks like the issue we’ve been discussing in MSFS Pop Out Panel Manager (with Touch Support) [v3.4.6]. I think the problem specifically with the CRJ is that for whatever reason it doesn’t store the size and location of its popout windows. And on top of that, CRJ windows pop out as nearly maximized.
This does not seem to be an issue with other aircraft such as CJ4, Kodiak etc. With the latter we can scale down the pop out windows and as their new position/size is stored automatically by MSFS, it’s easy to set them up for POPM addon.
Whether the above issue is with the CRJ or with MSFS, I cannot say.
I’ve read of a few workarounds (mentioned in that other thread) but the only one I found working for me is a crazy POV to capture as many windows as possible. Sadly not all (e.g. not the EFB or the RTU) but at least I can have most of them popped out and sent to a tablet via POPM addon and Spacedesk.