It is triggered when a filter icon is pressed. If this handler is defined the native filter window will not appear. In other words, the component’s handler will be replaced by the JS handler. Use this handler to create your own customized filter window.
params – the object which contains the following filter window parameters:
hierarchy– object that describes hierarchy
rect– object that describes filter cell’s
hierarchyName– the unique name of the hierarchy
caption– the hierarchy’s caption
x– the x coordinate of the filter window
y– the y coordinate of the filter window