Treeview NaviageURL and Target not working as expected

[hjp]

I have followed Steve Sharrock's example of setting up a
table in a aspx page, with a treeview menu in the left and
cell and an iframe in the right hand cell.

In his example when he clicks an aspx page listed in the
treeview menu it opens inside the iframe. When I try the
same with an html file as my treeview entry a new page
opens.

I have tried moving thru the treeview.htc file, but I
can't figure out when it opens the new page or how it
accomplishes it.

tia
hjp