Yes, much to the annoyance and/or amusement of others. I don't know if the good Doctor pulled that trick in the galleries, but I recall a few occasions here in the forums, especially the old OT forum in particularly lengthy going-nowhere threads.

Remember when someone (not naming names) discovered how to insert background images behind the thread text? Something nice, bright, and high-contrast flowery, that made it impossible to read anyone's posts?