Tables with sub-column headers (like in CMPPD) get messed up

[pcordes]

http://felixcloutier.com/x86/CMPPD.html is pretty messed up; the column headers seem to repeat everything. The main table body seem to be ok.

It's a tricky table because on "main" column has 4 sub-columns each with their own header.
https://github.com/HJLebbink/asm-dude/wiki/CMPPD formats the headers correctly, but the table is so wide that it needs a scroll bar. It's usable if you click in the table so you can left/right arrow to scroll sideways without having to leave your place to click on the scroll bar itself.