I installed 2.0beta6 on Ubuntu 16 - was straight forward - and compiled some scripts. All ok.
But I could not set a port. The only port available is /dev/ttyUSB0 and this is correctly shown under Tools->Port, but clicking on it has no effect. It is not selected. Likewise, using the "Select Other Board & Port" menu entry allows me to click on the correct (and only) port, yet no port is defined.
As a consequence I cannot upload any sketches.