Jitsi installs correctly under Ubuntu GNOME and it works correctly on a test SIP communication with video (provided you enable all protocols in Audio + Video before testing).
It starts to behave strangerly when you close the window. A warning tells you this won't terminate the application and that's fine, but when confirmed, the Jitsi icon drops in the upper left corner of the screen background instead of the system tray.
It is then unclickable, but if you right-click on the Jitsi icon in the dashboard, the menu contains a "New window" option that sometimes gets Jitsi back on the screen.
However, if you play a bit with the application and get error dialog boxes, it quickly ends up freezing and you have to kill it (application completely unresponsive, close button of the window has no effect).
Similar problems occur on Ubuntu Unity 15.10, but it is even worse on Linux Mint 17.3 Cinnamon, which I had to quit using.
I have tested each time with OpenJDK 7 and Oracle SDK 8 with the same result.
Have those issues already been reported to you ?
Do you have potential solutions ?
Is there anything I could do to help ?