[Stinger]

I've found some strange behaviour from the cover browser:

The cover browser functions as intended when I first start up Calibre. But certain actions seem to 'break' it so it's not interactive anymore (mousewheel, arrow buttons, or clicking on the side books no longer works). It still changes to the appropriate cover if I select a book in the Library list, but I can't navigate using the cover browser itself until the next time I restart Calibre.

Trigger:

EDIT: See my post below.