I am using Apex 20.1 and have a modal page with several page items. Two of which are radio group(parent containing Y/N options) and select list (child).
I have the child set up as cascading on the parent and have Items To Submit set to both items. The child list is the same for Y/N with the addition of two extra values for the N option.
If I have Y set for Parent and "Item 1" for child (which is valid for both Y and N) and then I change the parent to N, it clears out "Item 1" value in child and repopulates the list to include the two extra values.
If "Item 1" is valid for both parent options I want to retain that value so user doesn't have to reselect it again from the refreshed select list. How to do that?
I found an old example from Denes Kubicek (https://apex.oracle.com/pls/apex/f?p=31517:292:13831919832153:::::) from a previous version of apex and tried to implement the same but some of the options he specified no longer exist in Apex 20.1 and I could not get it to work.

Where I ran into trouble is in step 5 creating the Second Dynamic action Selection Type - DOM object , DOM Object - document
I do not have those options for the Selection Type. I only have Item(s), Button, Region, Column(s), jQuery Selector, and Javascript Expression. I tried using Region and then selecting the region where my items are but as noted it didn't work.
Is there a solution that works for Apex 20.1 to retain child id for cascading lov?