Currently the "Mass Update" feature in the "Edit a Keypress" dialog only supports changing matching keys.
Especially within the same command, it'd be handy if there was an option to do the same for all keypresses that match the delay of the current one(E.G. current keypress "A" has 0.1 delay, change to 0.2 with mass update, keypress "B" with 0.1 delay is now also set to 0.2, while keypress "C" with 0.3 delay remains unchanged).