This version introduces exactly one new feature, and exactly one tiny fix.
The new feature is that "filters" (hide invisible items from home, show collections only) can now be limited to the lower pane, instead of applying to both panes. This new option is accessible from the menu, and is disabled by default. You may find it useful when you want to quickly (manually) organize books into collections. The reason why filters can be restricted to the lower
pane (instead of to the upper one) is that this makes it possible to combine the filter function with the search function: You could use the search function from the menu bar to quickly find books by author (in the upper pane), while keeping the list of collections in the lower pane.
The tiny fix mentioned above concerns the naming of the search bar: It is now "Title / Author" (instead of "Title"), which more precisely describes its semantics.
Note that because of the new option, the translations need to be minimally revised.
Finally, @yiming: I think I have reproduced the bug with the search box disappearing. It happens when the device has entered sleep mode, and is woken up again. It can be triggered by manually pushing the power button twice with Collections Manager open. For the time being, I'll leave this as a "known bug", but I'm looking into it, and will try to find a solution. In the mean time, just don't let the device hang around idle for too long while having Collections Manager open