As I’m a big fan of “the best tool for the job” I’ve been switching between Windows and Linux according to whatever I’m doing and for no particular reason it seems I always ran Eagle CAD on Windows. As anyone else I have my settings file all prepared with keyboard shortcuts to the most used tools so I rarely have to click on the toolbar with my mouse.
Today I decided to stop using Windows for Eagle and installed it on my Ubuntu 14.04 laptop, as soon as I open the my current project schematic I started noticing that none of my keyboard shortcuts that use the <alt> key modifier were broken, <shift> and <ctrl> were fine.. well after some tweaking to map all the <alt> to something else I found out that the alternative grid will not work.. and there is no place were I can change that shortcut !
I searched all over the Unity configuration tools with no luck, nothing seemed to make the <alt> key behave as a modifier, instead it wanted to move windows around when I used <alt> + <mouse l-click>.
I was getting really angry until I found the solution here, it turns out it has nothing to do with Unity but with Gnome.
sudo apt-get install dconf-tools
Scroll down to org → gnome → desktop → wm → preferences → mouse-button-modifier → Set it to <Alt>+<Super>. Attention, do not leave it blank otherwise the modifier will always be active and you will not be able to click on anything.