When testing programming of expression maps, I have to close the window to try out new mappings.
For each minor adjustment I have to open the window again and navigate to the right articulation, again. As this is something that is done every minute, maybe 50 times in a session, you spend your brain on other task than the one at hand, making the process not only double in time, but maybe even quadruple, if not making the process impossible, as you maybe at the same time make changes to the instruments In question at the same time.
If there was an Apply button, I could keep the window open and have visual connection to the programming as I am working.