RC5: Cached entries not sortable, 0 thumbs folders

[Danny]

<Moderator's note: This topic was split from topic 'RC5: Default cache columns are too narrow'>

And while we're at it: enable sorting on them. You can't sort the list for numbers of thumbs which means you cannot delete folders with 0 thumbs easily. Why are those being cached anyway? And shouldn't they be removed when clicking "Optimize"?

XnView 1.80 <x>