The group dropdowns (as used e.g. in Forum when in separate groups mode) have a critical bug in the IE/JavaScript implementation which means that when used in IE7/8 (+older versions) you cannot navigate page with keyboard. As soon as you tab through the group selector, it reloads the page, taking you back to the top.

This is due to a logic error in lib/dropdown.js; the selectFocussed function, apart from being spelt wrong, is never called.

Moodle 2 does not suffer from this problem although there is a different related one. I have reported this separately as MDL-22517.