Command mode - also known as mouse pointer mode - is a mode in which the mouse is used to move a pointer (arrow) on screen to operate windows and menus. In this mode, a player may move, but may not change orientation, fire his or her weapon, or otherwise take many of the actions possible in action mode.
A player enters command mode whenever any user interface window is opened, such as the backpack, skills/abilities window, mission log window, and so on. Command mode may also be entered by pressing the CTRL key to access the radial menu or pressing the tilde (~) key.
To exit command mode, press the Escape key. All windows will be closed and the player will return to action mode.
You can also enter/exit Command mode by using the backslash (\) key. Is this a difference between FPS & MMO keystyles?