Just a reminder for myself and maybe useful to others too..
After re-installing Ubuntu and Blender, my 'alt' + 'mouse left click' to rotate view in Blender won't work anymore. I know I did something before - but I seem can't remember what. Actually, it is just as simple as changing 'alt' key shortcut to using those 'windows' key in Ubuntu system.
System > Preferences > Windows
Choose Super (or "Windows Logo") then.. close.
Open up Blender. everything works again :)
It will helps Blender runs faster too. It won't clash with Ubuntu shortcut anymore.
Cheers and happy Blending!
