Unable to deselect/untarget players via mouse

[psychicjinx]

After re-installing the game, the only way for me to deselect players is to press ESC on the keyboard as opposed to just clicking in a blank space with the mouse previous to re-installation. Pretty sure there are no missing files. Is there somewhere in the settings where you can toggle mouse controls? Thanks

[the_mexican_guy]

Make sure "Sticky Targeting" is activated under the interface settings.