We are loading and parsing modern/global/globalBindings.xml every time we display a message. We are doing this because are loading the tag "thumb-horizontal". I'm not sure what this tag is being used for nor why it needs loaded every time we display a message.
Looks like this thumb-horizontal tag is getting parsed in response to creating a gfx scroll frame. I wonder if this content node could't be cached somewhere so we don't need to hit the jar file every time an html iframe loads new content?
*sigh* marking invalid. Turns out my xul cache was somehow disabled. turning it back on removes this.