To do some stuff in Blender I need to use Alt key. It seems, however, that on Linux Ubuntu the left Alt can't be used for some actions(let's say, for example, Alt + RMB). However, when using right Alt key I than need to click the left Alt key, otherwise Blender goes to uneditable mode. I know that I could change Alt to something else, but I am used to it and I don't want to do so. So I rather wanna know how to prevent Blender from going into the werid mode(where I can't edit things).
This is because Ubuntu uses the alt key as a default-key. This worked for me.