Abacus 0.1.1 is broken in recent Mozilla builds. Sometime in the last six months, there was an upgrade to Mozilla’s XML parsing. The upgrade, thanks to some not-quite-sane sanity checking I did for 0.1.1, caused Abacus to hang Mozilla in an endless JavaScript loop.
Oops.
I’ve fixed that in my local Abacus, and with another fix to JSLib I’ve posted a patch for, Abacus 0.1.2 should be available soon. No new features, just making it work again. (Really, it’s ready now, but I want to upload it directly to mozdev, not here.)
Then I’ll start work on Abacus 0.1.3, which will be a bit streamlined and support much more MathML.