Yes, but if you push a cat away from the chest, the right click function is still not usable.
I am currently using Unity, maybe it is a conflict with Unity/HUD which uses tha alt key too. https://wiki.ubuntu.com/Unity/HUD
edit: nope changing hud's key to something else doesn't fix it.
Enabling VBOs solved the issue, but why was it working yesterday?
All the players can play on my realm now (at 1.9.1). 1.9.2 has been released is it working on your realms?
I can actually play on my realm now. Ubuntu 15.10
This happens to me.
When having 1.9.1 it says "Outdated server!I'm still on 1.9" and with 1.9 it says "Client Outdated"
It happens to me too, when i am teleported to an other map e.g. join a skywar game.
I also have Ubuntu 15.04 on an Acer Aspire E5-571, intel core i3-4005u, Intel HD 4400, 4 GB ram, Java 1.8.0_60, and linux kernel 4.2.0-040200-generic.
EDIT: I confused the right click with the left on description.I have now corrected it.