There is a tric on the example you have given.
The trick is as soon as you click on the "Filters" button, it will set a variable say vShow to 1 which will hide the button and make the textbox with listbox on top of them. Again as soon as you click on the Close button it will hide the textbox and listbox and make "Filters" button visible.
And you can place the listbox over the textbox.
In properties of the object, you will see the layout tab, here you can set the layers.