Opening a picture while in grid mode discards all rooms opened since the picture was shown in the timeline.

**Describe the bug**
Opening a picture sometimes makes rooms on the grid disappear, or appear again.

**To Reproduce**
I am not sure.

**Expected behavior**
The rooms on the grid do not change.

**Screenshots**
In order:

I click on the picture on the room up right (yep, that's a screenshot of hydrogen some minutes ago):

I close the picture, a room is gone:

I click on MTRNord's picture:

Another room takes the free place!

**Desktop (please complete the following information):**
- OS: Ubuntu 19.10
- Browser Firefox 78.0.2
- Version 0.1.25

**Additional context**
Add any other context about the problem here.