Can someone please help me to activate the cover browser of Calibre in Debian 7.3 KDE desktop (32 bit architecture)? I've tried toggling the arrow button in the bottom-right corner but unlike the other buttons, it yields nothing, not even a tool-tip when I hover over it. I've tried also clicking
Preferences > Look&feel > Cover Browser tab but there's nothing usable there. Please see the pictures below.
NOTE: I'm using version 0.8.51.