I've never encountered that behavior at all, either in IE 6, 7 or 8 or in FF 2.x or 3.x.
Only using IE 8 right now. don't remember how many machines Ive had this occur on, though I think more than one. (I maintain a "bunch" - but only use a few regularly.
IMHO, at this time IE 8 should be the that browser gets priority. Seems improved over previous MS browsers though it also seems to require more memory to perform well than them.