Different browsers have different capabilities, bugs, and developer facilities. IE's version trails behind because it throws out an unhelpful JavaScript error that I've already spent too much time failing to track down. There is a separate page on browser compatibility. Where possible, features are backported across versions - e.g. the shared dialogues.
There are extra controls at the top of the tree:
Refresh tree
Swap between all text, text with something there, or no text
Remove applied styles from selected element
