code: function(hideDelay) {
  			this._showByKB = undefined;
  			
  			if (this._timeout) {
  				window.clearTimeout(this._timeout);
  				this._timeout = null;
  			}
  			if (!this.isShowing()) { //$NON-NLS-0$
  				return;
  			}
  			if (hideDelay === undefined) {
  				hideDelay = this._hideDelay;
  			}
  			var self = this;
  			this._timeout = window.setTimeout(function() {
  				self._tip.classList.remove("tooltipShowing"); //$NON-NLS-0$
  				self._tip.removeAttribute("style"); //$NON-NLS-0$
  				if (self._afterHiding) {
  					self._afterHiding();
  				}
  			}, hideDelay);
  		}
docs: Hide the tooltip.