Table column header width is incorrect


I am trying to change the style of the row header column, so I am setting the following in CSS:

.v-table-cell-content-rowheader {
	padding-left: 10px;
 	padding-right: 10px;
 	color: red;

This, however, screws up the width of the column headers (screenshot below).
I tried to track the cause, and it seems that VScrollTableBody.detectExtrawidth() looks only at the first column to determine the extra width to add to each of the table column headers. This does not look right to me … anyways, does anyone have any suggestions on how to do this?

I worked around this by not setting the margin for the header cell, but placing a div in it, which has the respective padding.
It would still be good to know why the original approach does not work (and if it should work or not).