Re-entered everything, closed all windows, did a rebuild with no errors, but when I tried to reopen any of the pages with a MessageList on them (all others opened fine) it error'd & the collection was again empty. Entered just 2 items in a collection, saved, closed the window, rebuilt, re-opened with errors & empty collections. Re-entered 2 more lines (also - now instead of starting a line 0 it starts at line 154, so obviously the collection is occupied somewhere), saved, copied the object, went to another screen & pasted it, but it pasted with an empty collection. Went back to the other page with the object & it's collection was now empty. Tried this without saving or rebuilding & the collections were always empty when re-opened.