[oXygen-user] Inserting images via keyref - dialog requires Subtopic ID?

Hi there, I'm fairly new to oXygen, using v15.2. I'm having an issue trying to insert images that are referenced by keyref in a ditamap. If I insert the keyref in code view, the image appears fine, i.e. <image keyref="image-ref-keyname"> However, if I try to insert using the Insert Content Key Reference dialog, another dialog appears saying "Please select an element ID by pressing the Subtopic button". When I click the Subtopic button, no IDs appear. Is this expected behavior, or am I missing something? Thanks, Ed.