Product feature request (toggle method in sharpen tab)

When trying to decide on the amount of sharpening or the mode to use, I often toggle between choices to compare which is better. Having to wait for the software the reprocess each change slows down the editing process and makes the comparison process more difficult.

My suggestion is to have the software retain the last sharpening render in memory (if possible) and add a toggle method that allows the user to quickly switch between the existing sharpened image and the next method chosen.