I tried this Anchordocking and was unhappy with it.
One time it was there, the next start the docking was lost.
Then I read error messages "you cannot dock view what not docked" or similar.
You need at the very last to report those issues (On the bug tracker, after checking they aren't there yet). And with enough info to reproduce.
Otherwise nothing will improve.
My guess is, that maybe lots of the core developers prefer undocked windows. For example, I have multiple monitors and spread my Windows across them. Docking would be contra productive for me.
Actually, I have it running on one Linux VM (which is for coding only, no form editing). *IIRC* I had to set the current desktop to "default" and then save it => and since then the layout has been kept. But, I don't change the layout. I don't open new Windows. The VM is for running a few tests. So other than the code editor and a few debug windows, nothing else ever happens.