Went to Layer Properties Manager, clicked on "All", closed it, and now all layers appear in the Layor Control drop-down. Which is great, since that's what I expect. Can't seem to recreate the symptom though, which bugs me. There are only 2 filters- "All Used Layers" and "Xref".
Ah hah! - If I check "Invert filter" in the Layer Properties Manager the symptom sort-of reoccurs. Must have clicked on it by accident. But then, none of the Layers show up in the Layer Properties Manager when "Invert filter" is checked, and when the problem occurred earlier, they did. Hmm.
As you might guess, I seldom utilize filters.
Ralph
Structures Consulting
Northeast USA