How to Access Child Methods from Mdi Parent at Runtime

I am trying to write an Mdi application where the user picks a layout option from a Parent menu. This selection displays the required number of Child forms in the required layout. Then the user picks from a number of feeds to populate the active child form.

This Sub is one of a number of similar ones attached to menu items, in this case a single docked window is displayed (I have similar code for various numbers of forms and layouts).