Reproduction steps:
1. Open Collab window, using Collab button
2. Click on any other Editor window (like scene view, or hierarchy)
3. Collab window closes
4. Now open Services tab
5. Open Collab window and try clicking on Services tab this time
6. Window isn't closed

Also, closing using "Esc" button doesn't work. It makes it inconsistent with other pop-up windows.

These are cosmetic issues, but a little bit annoying.

Reproduction gif: https://gyazo.com/c88673b437e646c61bb987a5106061da