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
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.