Futher optimisation opportunity from bug 119286 comment 14 Quote: "We create a ton of small UNDO objects. Again, a smarter thing to do would be to create a single UNDO operation." This "is tricky because there are loops at multiple levels of the call stack, and it's not clear how the responsibilities are shared across the different calls." Perf can be tested like so: 1. Open attachment 144181 [details] 2. Disable the automatic spell checking if enabled 3. In the Search for field put "." (a single period) 4. In the Replace with field put "x" 5. Make sure Whole words only is unchecked 6. Click Other Options to expand the dialog, and make sure Regular expressions is checked 7. Click Replace All