Another update, mostly to improve reliability (I hope :P).
Many code tweaks under the hood to make sure SimpleUndoClose works as expected and hopefully a little more efficiently.
Also some visual tweaks like the awkward bold font of the search not found text is changed and the slider values in Options now update as you move the slider.
I want to have the current code running predictably and be reliable before I go on to whatever comes next.
EDIT: Found another problem but it doesn't seem to affect normal operations, 22.214.171.124 coming soon next week. Those having weird problems can try clicking the 'Clear' button to reset the state of the extension.