How to measure the actual width of row headers?

Im able to measure the actual width of the column headers by
width = grid.getTemplate("top/item", index).element().firstChild.scrollWidth;

I have set the row headers to custom strings and all I have to do now is to resize them accordingly. But the scrollWidth does not seem to be available for the row headers.

width = grid.getTemplate("left/item", index).element().firstChild.scrollWidth; width always equals 1

width = grid.getTemplate("left/item", index).element().firstChild.scrollWidth; width always equals 0

Any ides how to measure the actual width of the row headers?