As discussed in the Buttons and Pages section, there are many button types, including IA (Instant Access). IA buttons are the most general purpose type - they execute a list of Actions that can send MIDI messages and perform many other functions.
Note 1: This feature was introduced in earlier MIDI controllers, where it was often referred to as IA Reveal.
Note 2: The default Mastermind GT configuration is set up to use IA Mode and has an IA Mode button defined. The Mastermind LT and PBC are not set up to use IA Mode by default, but can be programmed to use it if desired.
Note 5: If you have Actions defined on a button, and Send on Preset Change is turned on for that button, the button's actions will be run every time you change presets. This will happen whether IA Mode is active or not.
More information about IA Mode can be found in Mastering the Mastermind Episode 3, MIDI Controller Basics (towards the end of the video) and Episode 7, Advanced Button Editing