I seem to have lost my + button

I had a working app, i could add new items to my table.
I’ve made some small changes, including an expression to one column.
Now i appear to have lost the ability to add new items in the app.

Help appreciated!

Could be several reasons for that.
But you need the table or slice to allow for ADDS under “Are updates allowed”.
And the system action “ADD” under the actual table must be displayed (under Apperance).