You may be aware that a "canvas" is necessary to display items in Forms. There are several types of canvassas, including:
content,
tab,
stacked,
. . .

A stacked canvas is used as follows:

Create a content canvas with the items you intend to display routinely. Create a stacked canvas, put content on it that you intend to display periodically, and position it over the content canvas in the appropriate location. Control the display of the content canvas, so as to make it appear that there is only one canvas, whose appearance has changed. In this way, you could put the data you wish to display in an LOV onto the stacked canvas, then display it at the appropriate time . . .

Good luck!