Cannot add rows to table in Data Explorer

Hello Peter:

Sorry, but I appear to have broken something with my composers table: I click on Data Explorer, find my table in the list and click ‘Explore’. The table’s rows are then displayed, along with an ‘Import’ button up top, but no ‘add new’ button.

Off the top of your head, can you think of something I may have done that would prevent me from being able to add new rows to the table via the Data Explorer screens?

I can fire up MySQL on the server and add additional rows directly there, but that’s obviously not as convenient!

I assume I must have switched on a ‘read-only’ mode flag somewhere, or something else equally dumb. My other tables in Data Explorer have ‘Add New’ buttons, no trouble: it’s just this one. Anything you can suggest to look at by way of table settings/design or what have you would be appreciated.

If you need all the gory details about the table design, etc. then let me know and I can put a page together with the relevant screenshots.

Sorry to bother you so soon, once more!
Regards
Howard