It's interesting. The variable view can be dragged from bottom to sidebar just fine. It gets a dispose and then recreated. But when that entire panel is moved it doesn't get a visibility change, or a dispose or anything like that which I can see. I might actually try to repro this with a super simple example and see if there is a similar issue.

I can actually repro this with the vscode webview-view sample.

The Calico Colors control also disappears when you move the panel. Oddly enough, just looking deeper now, there seems to be some sort of "welcome-view" element that seems to have replaced it?

Repro is just the same basic steps as initially listed using webview-view sample. I dragged the Calico Colors control from the sidebar into the bottom panel (still worked). Then I used Move Panel Right on the bottom set of panels. The control was gone and didn't come back for me.