Symptoms

There is a main form and 3 subforms namely subform1, subform2 and subform3. The main form will call subform1 then subform2 then subform3 and back to subform2. When you close subform3, it goes back to subform2 and the popup window just displays a grey color background.
 

Diagnoses

When looking at the rules configured in the main form, 2 other rules are executing the same rule “open subform 2” which will open subform2 as a subform:
1. When subform1 subform is closing
2. When subform3 subform is closing

It seems that when opening the same subview multiple times as part of the same action using if-conditions, the subview references are duplicated. Thus, the subview is not being rendered correctly.
 

Resolution

We have logged this as a bug to be fixed in the 4.7 release. As of now, there is no workaround.