'initial_polarity'::
On which child should a new window be attached when adding a window on a single window tree in automatic mode. Accept the following values: *first_child*, *second_child*.
+'directional_focus_tightness'::
+ The tightness of the algorithm used to decide whether a window is on the 'DIR' side of another window. Accept the following values: *high*, *low*.
+
'borderless_monocle'::
Remove borders of tiled windows for the *monocle* desktop layout.