Custom form will not load in calendar overlay view

I've created a calendar with a custom column (drop down box, 3 options). I created a view for each option in the choice column, then created calendar overlays in order to color code the calendar based on the choice. I then modified the default (calendar) view to only show when the custom column is blank, so that each item didn't display as duplicate. I then created a custom display form to hide a non-required field (description). If you click the item in the calendar overlay view, the default form loads, not the custom form I created. It will work, however, using the default view. I cannot find anywhere in designer or the browser that will use the custom forms in the other views.

Any ideas why the custom forms won't load in the overlay views?