rem: be.hidden = extraButtonLabel == null; 
add: be.hidden = extraButtonString == null; 
context:   setButtons: function(backButtonLabel, backButtonDisabled,                        nextButtonLabel, nextButtonDisabled,                       finishButtonLabel, finishButtonDisabled,                       cancelButtonLabel, cancelButtonDisabled,                       hideBackAndCancelButtons,                       extraButtonLabel, extraButtonDisabled) {    var bb = this.wiz.getButton("back");    var bn = this.wiz.getButton("next");    var bf = this.wiz.getButton("finish");    var bc = this.wiz.getButton("cancel");    var be = this.wiz.getButton("extra1");    bb.label    = backButtonLabel   || this._buttonLabel_back;    bn.label    = nextButtonLabel   || this._buttonLabel_next;    bf.label    = finishButtonLabel || this._buttonLabel_finish;    bc.label    = cancelButtonLabel || this._buttonLabel_hide;    be.label    = extraButtonLabel || this._buttonLabel_hide;        // update button state using the wizard commands    this.wiz.canRewind  = !backButtonDisabled;    // The Finish and Next buttons are never exposed at the same time    if (this.wiz.onLastPage)      this.wiz.canAdvance = !finishButtonDisabled;    else      this.wiz.canAdvance = !nextButtonDisabled;    bf.disabled = finishButtonDisabled;    bc.disabled = cancelButtonDisabled;    be.disabled = extraButtonDisabled;    // Show or hide the cancel and back buttons, since the Extra     // button does this job.    bc.hidden   = hideBackAndCancelButtons;      bb.hidden   = hideBackAndCancelButtons;    // Show or hide the extra button    be.hidden = extraButtonLabel == null;  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/dc004c63011ccdd5452590ad39266b9ba03f45cb/updates.js/clean/toolkit/mozapps/update/content/updates.js