• VS Code Version: 1.64.2

Steps to Reproduce:

1. try to move all icons in activity bar into panel or side panel.
2. only left with Explorer, Run and Debug, Remote Explorer and Extensions can't move.

Screenshot as below:

Except for Run and Debug, all other sub-items cannot be moved.
Can move Run and Debug's sub-items(watch, breakpoint....). but if only one item, can't move further.

I can't understand why Testing can, Run and Debug can't; Source Control can, Explorer can't.
Their views and interactions are so similar.

Also, I found #115641 and #142867 are exploring new layouts, so I excluded Manage and Accounts