Make it possible to select an anchor a second time on a xref

We use the imagemap inside a template.

This template already contains xref elements with predefined values for the outputclass and otherprops attributes.

We noticed that when adding an xref for the first time, it is possible to select an anchor in the target topic. However, when editing the same xref a second time, the option to select an anchor is no longer available.

As a result, we currently need to delete the existing xrefs and create new ones again. This also means that all attribute values must be entered again manually.

This process is error-prone and inefficient. In our opinion, it is also not logical that the anchor selection is only available the first time an xref is created.

For more information, please refer to support ticket CS0044827. Since this functionality has never worked differently, the ticket was closed because it was considered neither a bug nor a regression of existing functionality.