Fixing #230; add a scrollbar to the PM popup dialog if necessary. This wasn't as easy as I thought. Had to wrap the PM text in a div with its styling (max-height and overflow). If I then resized the dialog, I'd get two scrollbars. So for now, made the dialog non-resizable.

tinyMCE.addI18n('en.advhr_dlg',{
normal:"Normal",
width:"Width",
widthunits:"Units",
size:"Height",
noshade:"No shadow"
});