Hide empy index level in the Document's index tab
From the forum: https://forum.mayan-edms.com/viewtopic.php?f=9&t=2369
According to the report:
Indexes shared by two document types will product level which will contain: documents of type 1, documents of type 2, documents of both types.
If an index level has documents of type 1, then in the documents of type 2 index tab, the level will still appear but will be empty. The correction proposed is to not show indexes whose results are empty for a given document, in it's index tab.