Message is currently:
Data for atleast one patient needs to be filled in !
(with the extra space before the exclamation mark)
(not getting into the data plural/singular debate)
Thinking about it, the message is odd, as your attempt is not about filling it in, it is about deleting patients.
Possible alternative:
"Patient cannot be removed, at least one patient is required for the analysis".
I think, if there is only one patient, there should be no Remove button. Giving user a button just to tell him he cannot use it is not very user friendly.
Message is currently: Data for atleast one patient needs to be filled in ! (with the extra space before the exclamation mark) (not getting into the data plural/singular debate)
Thinking about it, the message is odd, as your attempt is not about filling it in, it is about deleting patients.
Possible alternative: "Patient cannot be removed, at least one patient is required for the analysis".