Just use standards, then tweak the browsers to make them right. It's a
shame that no browser maker(IE team) /framework(creators of webparts,
tree control, and Wizard) creator ever obeys the W3C (well, Mozilla
does). Just imagine a world where 1+1=2 for you and 1+1=3 for someone
else... that's web development. There is no interop... even though
that's the entire point.
Like I say all you can do is obey the W3C, then add backwards compat to
IE and add a few fixes to fix the ASP.NET code to make it work in real
web browsers. Have fun trying to get anything working in Opera
though... you may want to back away from trying that.
DB
http://www.davidbetz.net/dynamicbliss/