I have annotation where a single annotation feature consists of one or more TextElements and RectangleElements grouped together in a GroupElement and then stored in the annotation feature. To edit the contents of the annotation feature later, it would be nice to be able to know which elements are related to each other. The elements have natural groupings, but those groups cannot be grouped together and then grouped into the final GroupElement for storage. Due to a bug, the ESRI optimized map service cannot handle nested groups in annotation. (See this posting.) So all elements just have to be thrown in together. An identifier object, holding, say, a group name string, attached to each element would make identification of elements belonging to each subgroup much easier to identify. The Avenue ObjectTag object in old ArcView GIS 3.x (I guess it was a property) used to be great for such things. You could stick a tag on just about any object in the whole model, including dialog controls. Really handy. I haven't thought about this -- until recently -- since the old Avenue days, but it has now come to my consciousness again. I haven't been able to find anything like the old ObjectTag in ArcObjects. Any ideas?
I guess the most direct equivalent in ArcObjects would be