Adding a DOCTYPE,
to the reorder.html TreePanel example causes animation of nodes to appear (briefly) outside of the container it occupies. This is somewhat annoying.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
To reproduce, add the above DOCTYPE to reorder.html, then expand nodes such that the scrollbar appears. Expand "experimental" node, then collapse it. You should see a brief flash of the child nodes outside of the container while animating. This does not occur in the example w/ DOCTYPE missing.
Observed on IE 6.0 Windows (not tested on others)