Hi Dave,
Just want to add one thing based on what David mentioned above - that there is also another way to work around this if you do ever come across the situation where you need multiple widgets inside a controller (prior to the fix):
In the Filter widget setting, now it is possible to choose more styles as "Arrangement Style > Icon". If chosen, then the UI would resemble what is inside the controller and the widgets represent as an icon with a pop-up, you can even change the width, height, corner radius, and background colors.
Anyway, it might be fun to explore that
Cheers,
Tonghui