Thanks Gary, that was it. This is a very large table and I had not scrolled down far enough to see there was empty space below the table.
Hi Barry,
A short time after I posted my reply, this occurred to me also, but I'd shut down my machine ready for bed

and I guessed (correctly) that someone would also figure that out...
Welcome to EA's UI (
Unique Interface)... Of which - if you read my posts -
I'm not a fan...You may wonder, as a new user,
why the
Statechart Editor is NOT an option on the
Diagram menu when it is
clearly a Diagram context Menu item?
Especially when (as you've observed) if the table occupies the entire panel it isn't intuitive that you need to find some spare diagram space to activiate the context menu.
Since the item doesn't exist as an auxliary item on the context menu for the table cells.
You will need to get used to some functionality being available in one menu and not the other (with no apparent rhyme or reason), in some cases, I believe, the apparently same menu item in both places actually behaves differently...
Enjoy...
Paolo
(Still here after more than two years - in spite of EA - not because of it)