It seems like this is a good place for a spinner, not just some text.
Add an activity indicator for AJAX calls.
Review Request #798 — Created March 31, 2009 and submitted
Add an activity indicator for AJAX calls. This activity indicator is triggered during AJAX operations such as fetching the review form, marking a change as submitted, saving comments, or saving parts of review requests. This appears in the top-right of the page in a simple but eye catching little box, regardless of where you are on the page.
Tried saving data in review requests, making comments on diffs and screenshots, bringing up the review dialog, and marking changes as submitted, discarded, and reopening reviews. Saw the "Loading..." or "Saving..." indicator as appropriate.