To check things for a test project (El Capitan / 2019r2), I loaded an example project (yesterday).
Today, I started by deleting the entry for that project (*).
Then, angst: I cannot click in Cancel (why ? I do not know), so I pressed the OK PushButton (who was active even if no entry was selected ) and the example project was opened. (No coffe before coding Emile ?)
Yes, I too coded like that too, sometimes ago. And after making many times the mistake, I made a change to never have that (now, on image drop, I delete the previous result and disable the Save button, so only the Process button is active/Save is disabled until Process was hit; I cannot anymore save a previous image by error, errors are so easy to achive ).
(*) There is no explanation on screen on how to delete an entry in the New project
window (IDE); and yes, using the Delete key is intuitive.