All credit for this one goes to @tnkz76!
HELP
Shift+0: Display Help screen.
Editing a Text Field
Shift+Arrows/Encoder: Move the cursor to the beginning or end of the field.
During editing, Shift+Arrows/Encoder scroll to the beginning or end of the alphabetic characters.
Tabbing
Shift+Enter or Shift+Encoder: back-tab (e.g. in Sampling, Pan, Waveform Editor, Envelope Editor)
Holding down Enter or the Encoder while pressing the Arrow keys or turning the Encoder also tabs forward and backward between fields.
Browsing Files and Folders
Shift+Arrows/Encoder: Scrolls to the first or last file.
Shift+Back: Goes up one folder level.
Track Settings
Shift+Pad: Displays Track Settings
Shift+Pad in track settings switches track without playing sound (pressing pad without shift plays sound)
Playing Patterns
Shift+Run/Stop:
â—ŹWhen stopped, Shift+Run/Stop continues playing from the point at which the pattern was stopped.
â—ŹWhen running, Shift+Run/Stop restarts the pattern at the beginning. If the pattern number has been changed, but the current pattern is still playing, Shift+Run/Stop immediately starts the new pattern.
â—ŹWhen using an external clock source, Shift+Run/Stop forces the pattern to play even if no external clock is being received, or forces the pattern to stop if it is already playing.
Recording Patterns
Rec/Edit+Run/Stop: To begin recording, hold the Rec/Edit key then press the Run/Stop key.
Pattern Tempo
Shift+Arrows/Encoder changes the tempo in 0.1 BPM increments.
Shift+Tempo: Toggles global tempo or pattern-specific tempo for the current pattern.
Repeat
Tap/Repeat+Pad: Hold the Tap/Repeat key while pressing a pad to repeat the track.
Shift+Tap/Repeat: Locks repeat mode. Press and release Tap/Repeat to unlock repeat.
Pattern Mode Keys
Shift+A: Displays the parameter settings for the current fader mode.
Shift+B: In Mix, Level, or Pitch fader mode: Filter settings. In Envelope mode: Switch envelope.In Loop/Slice mode: Toggle looping
A+Pad: Shortcut to Modify Pattern.
B+Pad: In Mix, Level, or Pitch fader mode: Shortcut to Modify Pattern for the filter.
Shift+Bank: Goes to the previous bank.
Bank+Number Key: Goes directly to a bank (Bank+1 for A, Bank+2 for B, etc.)
Shift+Back: Stops all sounds in any mode.
If the current bank is a MIDI bank, Shift+Back does a “MIDI panic” and sends an all notes off CC message, and a note off message for every note, on all of the ports and channels that have MIDI tracks.
Back+Pad: Resets all sound parameters (level, pitch, filters, etc.) to their defaults for that track.
In Multi Mode, Back+Pad resets that track’s multi parameters for the current fader mode (pitches, slices, etc.).
Erase+Pad: Quick erase the track from the current pattern, or selectively live-erase events.
Copy+Pad: Select a pad to copy. Continue holding copy, then press the destination pad. In Multi Mode, the same action copies parameters from one multi pad to another.
Undo
Copy+Back: Undo/Redo
Copy+Enter: Set manual undo point
Copy+0 (zero): Cancel manual undo point
Additional shortcut for UNDO
Back+<<<: Undo
Back+>>>: Redo
Back+0 (zero): Set a manual undo point
FADER MODES
Shift+fader:
â—Ź If the faders are locked, holding Shift while moving a fader will modify the parameter
â—Ź If the faders are not locked, holding Shift moves the fader without modifying the parameter.
Parameter Settings
Shift+A: Displays the parameter settings for the current fader mode.
Shift+B: Displays the filter settings when in Mix, Level, or Pitch fader mode.
In Envelope mode: Switch envelope.
In Loop/Slice mode: Toggle looping.
A+Pad: Shortcut to Modify Pattern
B+Pad: Shortcut to Modify filter
Multi Mode Sync Settings
Press Shift+MultiMode to display the Multi Mode Sync Settings menu.
Envelope Fader Mode
Shift+A: Displays envelope settings
Switching Envelopes
Shift+B: Switches between envelope 1 and envelope 2, and the classic envelope if it is enabled for the track.
Loop/Slice Fader Mode
Shift+A: Displays slice settings
Shift+B: Turn on looping.
Waveform Editor
Shift+A: Displays slice settings
Shift+B: Turn on looping.
Back+Pad: Reset the points to where they were when the editor was first displayed.
Shift+fader:
â—Ź If the faders are locked, holding Shift while moving a fader will modify the parameter
â—Ź If the faders are not locked, holding Shift moves the fader without modifying the parameter.
Shift+Enter or Shift+Encoder: back-tab. Holding down Enter or the Encoder while pressing the Arrow keys or turning the Encoder also tabs forward and backward between fields.
Shift+Arrows/Encoder: Always scrolls the screen no matter which field is selected (when zoomed in)
Arrows/Encoder: Change the value of the highlighted field. When editing slice,
Shift+Arrows/Encoder changes to the next/previous multi slice.
Metronome
Double click: Quickly double-clicking the Metronome key toggles the metronome on/off for the current mode.
Swing
Swing key+arrows/encoder: Changes the pattern’s swing setting in pattern mode
Swing key+pad + arrows/encoder+pad: Changes an individual track’s swing in pattern mode.
Quick-Erase Track
Erase+Pad: (hold Erase, then press a pad) erases the entire track from the current pattern without having to go to the erase menu.
In Multi Mode, Erase+Pad erases only pattern events recorded with that multi pad.
Live-Erase Events
While recording, holding Erase+Pad removes events from the pattern as the track is played in the pattern.
Quantize
Quantize+arrows/encoder: Changes the default quantize setting in pattern mode.
Quantize key+pad + arrows/encoder+pad: Changes an individual track’s quantization in pattern mode.
STEP PROGRAM
Shift+Run/Stop: Play from the current cursor position
Erase+Pad: Removes events from the pattern at the cursor position or in the selection.
Erase+Enter/ Erase+Encoder Press: Removes all events from the pattern at the cursor position.
F4+Pad: Shift one track’s events under the cursor or in the selection
Shift+Encoder/Enter: Selects the pattern number.
Bank+Arrows/Encoder scroll vertically by one track if there are more than 8 tracks.
Tap/Repeat+Pad: Adds event, then moves cursor to next step.
Select and Copy
Shift+ Encoder/arrows: select an area of the pattern.
Erase+Enter/ Erase+Encoder Press: Removes all events from the selection.
Erase+Pad: Erase one track’s events from the selection
Copy+Pad: Copy one track’s events from the selection (or under the cursor) to the clipboard.
Shift
F4+Pad: Shift one track’s events under the cursor or in the selection
TR Mode
Shift+Mute/Solo: Display Edit Step Parameters for that step, if there is an event there.
Tap/Repeat+ Mute/Solo: Adds or removes a step in all measures
Edit Step Parameters
Shift+Enter or Shift+Encoder: back-tab. Holding down Enter or the Encoder while pressing the Arrow keys or turning the Encoder also tabs forward and backward between fields.
Mute/Solo
Mute/Solo Undo/Redo
•Shift+any mute button: If any tracks are muted, un-mutes all tracks.
•Shift+any mute button: If no tracks are muted, re-mutes what was previously un-muted.
•Shift+any solo button: If any tracks are soloed, un-solos all tracks.
•Shift+any solo button: If no tracks are soloed, re-solos what was previously un-soloed.
•Bank+Mute/Solo/A/B: Toggles mute, solo, override or overwrite for all tracks in the current bank at the same time.
•Bank+Mute mutes or unmutes all eight tracks in the current bank. Bank+Solo works the same way.
LIVE LOOPING
Shift+Pad: Displays Live Loop settings and functions.
Erase+Pad: Erase one of the Live Loops.
Shift+Mute/Solo: Turn the Live Loops on and off using the opposite of the immediacy setting for that Live Loop.
Pressing Erase+A/B for Live Loops is an alternate way to erase the Loop/buffer
SONG MODE
Shift+Run/Stop: When no song is playing: start the song from the selected step.
SYNC
Clock Source
Shift+Run/Stop: Force the S2400 to run.
Run/Stop+Rec/Edit: Arm the record function
Shift+Run/Stop+Rec/Edit: Force the S2400 into record mode.
SAMPLE MODE KEYS
Shift+Enter or Shift+Encoder: back-tab. Holding down Enter or the Encoder while pressing the Arrow keys or turning the Encoder also tabs forward and backward between fields.
MIDI Track Settings
Shift+Pad: Display MIDI Track Settings
Save
When the “Cannot Save while running” prompt is displayed Press Run/Stop to stop and save and start playing again (only works for existing projects).
Effects
Analog Filters Press Shift+Enter/Encoder to toggle all of the filters at once.
Keyboard Shortcuts
BONUS
Shift+Back+Enter: Reboot
Shift+Song: screen capture
Shift+99 in Settings : Brad’s Christmas Egg 
Shift+@!#?@! : PONG 
HELPFUL LINKS
S2400 Tips And Tricks Wiki
Video Manual Playlist
Docs and Downloads