When the toolbar position is "fixed", the preview mode does not hide the toolbar.

[itribs]

Describe the bug
When the toolbar position is "fixed", switching to reading mode will hide the toolbar. However, when switching to another note, the toolbar will reappear, and it is still in reading mode at this time.

Expected behavior
The toolbar should remain hidden until switching to edit mode.

Desktop (please complete the following information):

• OS: Ubuntu 22.04