Things

Three bug fixes
I think so, to. It could be disabled on Linux by default. I read that on some distributions it works and on some other distributions (e.g. on Ubuntu with Unity) not.
I recommend a source code like this:

bool iconDefault;
#if  Q_OS_LINUX
iconDefault=false; // we guess, that it doesn't work
#else 
iconDefault=true; // Windows® or Max, on which it should work
#endf