This command enables or disables MIDI learn mode. Learn mode makes it easier to set up mappings so that properties can be remotely controlled, typically via a MIDI control surface. Learn mode is only effective if the Mapping bar is visible and at least one mapping is selected. While learn mode is enabled, any mappings selected in the Mapping bar are highlighted in green.
In learn mode, if a MIDI channel message is received from the input MIDI device, any selected mappings automatically snap their input properties to match the received message. This is often easier than setting the input properties manually, and makes it unnecessary to know what MIDI messages the control surface sends for each of its controls.
Be sure to disable learn mode when you're done learning input MIDI messages, otherwise you may unintentionally change your mappings the next time you touch the control surface. See also learning mappings.