If you add or delete
a row to or from a section, or if you change the geometry
of any of the rows in that section, you may need to update the bounding
box for that section.
XkbComputeSectionBounds examines all the rows of the section and updates
the bounding box of that section so that it contains all rows. XkbComputeSectionBounds
returns False if any of the arguments is NULL; otherwise, it returns True.