Microsoft just released version 8 of their Internet Explorer browser (IE 8). Some of your students may have installed this on their computers. If they have, please suggest that they use Firefox instead. Please notify your online students that they may have problems using IE 8 with Blackboard to deter them from upgrading if possible.
The Compatibility View toolbar button in IE 8 does not solve all the problems your students may experience with Blackboard. One of the problems they may report is that they can't submit a timed test because the timer button is too big and is covering the Submit button. They may also have trouble submitting assignments.