Vertical anchor is one of: <anchor_vertical_top>, <anchor_vertical_center> or <anchor_vertical_bottom>.
Horizontal anchor is one of: <anchor_horizontal_left>, <anchor_horizontal_center>, <anchor_horizontal_right>.
If none of the tags are present, these default values are used:
The defaults for the main Simple View background are <anchor_vertical_top> and <anchor_horizontal_left>.
The defaults for the Simple View Preferences dialog background are <anchor_vertical_center> and <anchor_horizontal_center>.
