At least when in non-3D mode (i.e., when looking like an old-fashioned
TWM), the value of the TitlePadding .vtwm directive is correctly used
to calculate the padding between the left title button(s) and the
title, and between the title and the highlight area, but the highlight
area is not adjusted in width to make sure that there is also
TitlePadding pixels between it and the right title button(s).
As a result (for instance), setting TitlePadding to 0 will cause a
large gap between the hightlight area and the right title buttons, and
setting it to 16 will cause the highlight area to collide with the
right title button.
This does not happen in TWM; consider stealing correct code from there.