shortcut-keys
I really like some of my shortcuts but I find at times there are other ways I would like to invoke the same shortcut.
For example:
Ctrl + Alt + Left/Right
Switches workspaces left/right respectively.
I want a mouse click to perform this same functionality. My mouse wheel can go left/right and I want to map this to go left/right in my workspaces but I also want the keyboard shortcut to remain.
So as noted in Sathya's comment, he is running under Vmware.
The reason this doesn't work is because VMware Player is taking control of Ctrl+Alt, because that's the key combination it uses to "break out" of the VM.
There are two ways you can fix this:
There is an escape override built into VMware which overrides the breakout combination, by tapping Space while holding down the breakout combination, before hitting your desired key So for example, if you wanted to go to the right workspace you would hold down Ctrl+Alt, tap Space and then tap Right.
Change the breakout combination. To do this, edit preferences.ini (in Windows 7 it's in C:\Users\$YOUR_USERNAME$\AppData\Roaming\VMware, if you can't find it search) and add:
pref.hotkey.shift = "true"
pref.hotkey.alt = "true"
pref.hotkey.control = "true"
This remaps the breakout combination to Ctrl+Alt+Shift.
Before you say anything, yes, I realise that this is also used in Ubuntu, to move windows between workspaces. Unfortunately, that is the best I've been able to come up with so far. You are supposed to be able to be as specific as left or right control, but they don't work for me, leftControl etc just maps back to both.
References:
These settings are normally found in Keyboard Shortcuts:
System > Preferences > Hardware > Keyboard Shortcuts
Click where it shows the key combo or says 'disabled' and press the key combination you want.
If you cannot use this feature for some reason or you prefer a CLI method, use Gsettings.
Here are all the possible keybindings for workspace manipulation and their likely default values:
org.mate.Marco.global-keybindings switch-to-workspace-left '<Control><Alt>Left'
org.mate.Marco.global-keybindings switch-to-workspace-11 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-10 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-1 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-12 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-4 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-2 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-3 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-7 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-5 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-6 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-8 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-prev 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-right '<Control><Alt>Right'
org.mate.Marco.global-keybindings switch-to-workspace-9 'disabled'
org.mate.Marco.global-keybindings switch-to-workspace-down '<Control><Alt>Down'
org.mate.Marco.global-keybindings switch-to-workspace-up '<Control><Alt>Up'
org.mate.Marco.window-keybindings move-to-workspace-8 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-10 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-12 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-11 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-left '<Control><Shift><Alt>Left'
org.mate.Marco.window-keybindings move-to-workspace-down '<Control><Shift><Alt>Down'
org.mate.Marco.window-keybindings move-to-workspace-1 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-2 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-3 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-4 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-5 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-6 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-7 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-9 'disabled'
org.mate.Marco.window-keybindings move-to-workspace-up '<Control><Shift><Alt>Up'
org.mate.Marco.window-keybindings move-to-workspace-right '<Control><Shift><Alt>Right'
org.mate.Marco.window-keybindings toggle-on-all-workspaces 'disabled'
To change one use the gsettings set command, for example
gsettings set org.mate.Marco.window-keybindings move-to-workspace-3 '<Mod4>3'
This command sets super+3 as a shortcut to move the current window to workspace 3.
To remove a keybinding, set it to 'disabled'. See man gsettings for more detail. You may have to experiment to achieve exactly what you want.
Best Answer
If you are using Compiz (chances are that you are) you can install Advanced Desktop Effects Settings (ccsm), either from the Software Center or from the command line
Now go to System-> Prererences-> CompizConfig Settings Manager.
Click on the Viewport Switcher icon. The window should change, go to the Desktop-bases Viewport Switching. Click on the buttons after Move Prev and Move Next (labeled Disabled on the screenshot). A new window will open, click enabled, another one will open, here you can select a mouse button for each action there, always or only when the mouse is in some screen places or when a special key is pressed.