Hi there! Found a using case which looks like a bug.

Describe the bug

The top right screen corner panel disappearing after switching preview mode in the pattern editor.

To Reproduce

Step 1: Go to https://wordpress.org/patterns/new-pattern/
Step 2: Click to the preview mode icon on the top right screen corner and switch the preview mode to mobile
Step 3: Click to the "Type / to choose a block" in the content editing area. It will trigger disappearing the top right screen corner panel.
Step 4: Click to any place in the content area outside content blocks. The top right screen corner panel won't appear again so you will not be able to save you changes.

Screenshots