Apex 21.1.7
In a Static Content region I have a page item of type Popup LOV with a dynamic action for event "Change". The only action of that DA is executing Javascript code: alert("...");
Now when I open the LOV and select the same value as the current value, the alert is shown. This is of course only a test case.
I think the behavior in Popup LOVs should be the same as with select lists, meaning Change event is not triggered when the value is not changed.
As workaround for "real" Popup LOVs I use a hidden item which holds the old LOV value. When the current value of the Popup LOV is the same as the old value I immediately cancel the DA. Otherwise the hidden item is set to the new selected value.
Regards,
Christof