code: function mixInto(fnClass, bDefaultValue) {
  			// add the properties
  			fnClass.getMetadata().addSpecialSetting("stashed", {type: "boolean", defaultValue: !!bDefaultValue});
  
  			// mix the required methods into the target fnClass
  			fnClass.prototype.setStashed = function(bStashed) {
  				if (this.stashed === true && !bStashed) {
  					if (this.sParentId) {
  						var oControl = unstash(this, sap.ui.getCore().byId(this.sParentId));
  						// we need to set the property to the stashed control
  						oControl.stashed = false;
  						return;
  					}
  				} else if (bStashed) {
  					Log.warning("Cannot re-stash a control", this.getId());
  				}
  			};
  
  			fnClass.prototype.getStashed = function() {
  				return this.stashed;
  			};
  
  			var fnDestroy = fnClass.prototype.destroy;
  			fnClass.prototype.destroy = function() {
  				delete stashedControls[this.getId()];
  				fnDestroy.apply(this, arguments);
  			};
  
  			fnClass.prototype._stash = function(sParentId, sParentAggregationName) {
  				// for later unstash these parent infos have to be kept
  				this.sParentId = sParentId;
  				this.sParentAggregationName = sParentAggregationName;
  				stashedControls[this.getId()] = this;
  			};
  		}
docs: private function without validity checks