Window focus changes improperly

To reproduce:

- enable focus : follow mouse pointer in terminator preferences.
- split terminator in two windows.
- place mouse cursor on left split term
- press alt arrow right, to switch focus to right term.
- alt tab into another application , then back into terminator

Result:
since this tabs out of the terminator application when it switches back
the focus will set to where the mouse cursor is. not where we specified the focus to be using the keyboard.

Proposed fix:
Perhaps keep track of coordinates of mouse cursor x,y since last focus change. if last focus action was made by keyboard &
mouse coordinates are within the same terminator split as during last focus change. Don't switch focus