Good to hear that the Debian/Mint compatibility is working as expected. Thanks to @Akishin.
It's a known issue that we don't have full try icon support with Qt 5. You can work around this by running :
to bring up the settings window directly. See the included README. Without the green icon it may be hard to diagnose problems, but you ought to be able to see the framerate in the Tracking tab.
To see if the daemon is detecting the device at all, run it directly :
service leapd stop
and see if it mentions anything about detecting the Leap Motion embedded controller module. If not, well we may have some ideas for that.