sorry, but I don't know the English expression for the tool. In german it is Bereichsreparatur. With this I remove a blur on the picture coming from dust on my lense.
I think so you are talking about " Spot healing ".
So once you have used the Tool, please click on " Fertig" on the bottom right of the image.
And then try and use the Arrow Keys.
many thanks. I am angry about myself! Im working for more than 1 year with this software and haven't seen this button!
You are Welcome, Glad to Help.