If parent data type is "Value" the form editor does not work as expected
Maybe this is a misunderstanding (or a lack of info) on what the "Value" data type is in dmx.
In any case (on demo.dmx.systems) when I create a new Composite topic type (dataType "Value") and associate two new child types of type "Text" (Cardinality: One) and then create and edit instance of such type the editor does not update the values I entered into the input field (one is lost) and the topic is rendered empty after my edit.
E.g. try editing an instance of type "Test" on https://demo.dmx.systems/systems.dmx.webclient/#/topicmap/2848 (today). If I change the composite type to "Identity" the form behaves as expected and my edits are persisted.