Be careful with old versions!
These versions are displayed for reference and testing purposes. You should always use the latest version of an add-on.
In this bug, TextAreas and InputFields would disappear.
This has been resolved by getting a new baseline for the platformHTMLBindings.xml file, which included a bindToUntrustedContent="true" annotation on the keybindings for TextAreas and InputFields.
This version does not work (well) with Firefox 29 and higher, and breaks in an impressive fashion on Firefox 34 by removing text boxes.