In Ableton, when a track with a Drum Rack is selected, the Note Mode on the Launchpad X or Pro MK3 will change the layout to create a visual representation of the Drum Rack you are controlling.
The view is divided into four 4x4 areas, each of which represents the areas of the Drum rack, shown below.
This layout is assigned to MIDI Channel 2 within Ableton so long as you have set up your Launchpad X or Launchpad Pro Mk3 with Ableton as outlined in the below articles
When setting up a Drum Rack and another MIDI instrument you will find if both MIDI tracks are enabled you will hear both channels when using the Drum Rack. You will need to assign the Drum Rack to MIDI Channel 2
You will find when assigning the Drum Rack to any channel other than All Channels or MIDI Channel 2 the drum mode will appear to freeze. This is because what you see on the Launchpad is still a representation of that Drum Rack, and that Drum rack is not receiving MIDI.
The Launchpad will still send MIDI data, however, as the Drum Mode is assigned on Ableton as MIDI Channel 2 the Drum Mode will not function on other Channels. To 'unfreeze' this please change the MIDI channel of the drums back to Channel 2 or All Channels.