I have Ubuntu and GNOME 3 and when I do Alt+Left-click it grabs the current window. How do I stop this from happening, as I need this shortcut in Blender which I update often so changing it inside Blender is not logical.
In your Compiz Config Settings Manager click on "Move Window" plugin. Click on the very first mouse shortcut (it should be
<ALT>Button1) and Disable it.
If CompizConfig doesnt work for you, try this:
Fix using dconf Editor
Install dconf Editor:
sudo apt-get install dconf-editor
Search for dconf Editor in dash and run it, then search for
mouse-button-modifier and change the key from
<Super> or anything else. That worked for me.
Try using Xubuntu instead. I struggled a bunch with this, and was pointed toward Xubuntu because its interface steals from apps less, and is more customizable.