Today I tried to use two DOM:s in the same way you use one DOM and one IGM in the image gallery module.
Since I'm posting here I obviously failed.
I've gotten partway there.
$cityManager->setFilter('CountryID', 'Choose a country', $this->Countries()->toDropdownMap('ID','Title'));
I get the filter I want but the filter setting isn't used when saving the object. I also tried setting a default value for the filter but I noticed that the select box resets itself everytime you make a choice if you put a value as the last argument in setFilter.
So the questions:
1. Can the option No filter be removed like in IGM?
2. Is the select box supposed to reset when making a choice if the default value is set?
3. Can the value from the filter box be used when creating new objects just like for the IGM?