To clarify things, I have attached four files. Here are the steps to reproduce the problem:
1. Place all four attached files in a single directory on disk.
2. Load DYN.HTM in Firefox with Firebug on.
3. Click on Firebug's "Click an element in the page to inspect" button.
4. Click on the text inside the rectangle. This will bring up the HTML inspector on the text.
5. Click on the text outside the rectangle a few times. Notice that the style of all the text changes, and 'class="highlight"' inside the HTML inspector toggles on and off, as they should.
6. Now, right-click inside the rectangle and select "This Frame > Reload Frame".
7. Repeat steps 3-5. This time, even though the text style changes, as it should, the class shown in the HTML inspector does not change this time.
This seems like a bug in Firebug. Should I report it?
This is looking like the problem described in issue 5705.
Thanks for the detailed description and clear test case! I attached it to that issue.