How to disable the Dock:

Choose Settings > Disable Dock.
For keyboard-affine and power users, the Dock often stands in the way. Even with auto-hide on, you may to disable the Dock completely so that it doesn’t appear unasked.
Choose Settings > Disable Dock.
To enable the warning again, choose Settings > Enable Dock.
Important: the Dock will still appear when running apps in full-screen mode. This is not a MainMenu bug — Mac OS X doesn’t allow it.