tips.txt

TIP Right-drag the arrange view to marquee select items
TIP Alt+right+drag the arrange view to marquee select items while setting time selection
TIP Alt+drag a media item to slip the content left or right without moving the item itself
TIP Right-click on empty space near the main toolbar to customize the toolbar
TIP Shift+drag over existing data in a MIDI CC lane to create linear ramps
TIP Hold down shift to disable grid snapping
TIP Control+drag faders for finer control
TIP Drag IO buttons to other tracks to create sends (shift+drag for multiple sends)
TIP Control+shift+drag MIDI notes and envelope points to move in one direction only
TIP Hold shift to move both sides of a crossfade together
TIP Control+drag empty track space to copy the selected item or create a new MIDI item
TIP Enable track free item positioning to free your mind
TIP Items can be set to always replace or always mix with later items on the track
TIP Unlink loop points and time selection in the Options menu
TIP Shift+drag a time selection to move both sides together
TIP Control+click recarm, FX bypass, mute, or solo buttons to disengage for all tracks
TIP Shift+middle mouse button drag to hand-scroll through the project
TIP Middle mouse button drag to scrub audio
TIP Open the plug-in pin connector (ins/outs button) to reroute plugin inputs/outputs
TIP Drag the plug-in wet/dry indicator to mix dry signal with plugin output
TIP Control+drag to freehand draw automation envelopes
TIP Right-click an envelope to interactively reduce envelope data
TIP Enable ripple editing on the toolbar to have edits ripple through the project
TIP Right-click everything to see what it does
TIP View the master track and its tempo envelope to edit tempo/time signature changes
TIP Record track output to non-destructively render synths/FX/automation
TIP Make the mixer taller to see the extended mixer: FX, sends, and FX controls
TIP Press "?" to open the actions window and a world of possibilities
TIP Double-click empty track control or mixer space to create a new track
TIP The transport slider changes master playrate (varispeed) for the entire project
TIP Alt+drag the edge of a media item to timestretch it
TIP Drag or alt+drag (timestretch) a split with both items selected
TIP Item Properties dialog allows precise stretching, shifting, reverse, etc
TIP Every item has a volume handle at the very top
TIP FX can be applied to individual takes
TIP Control-click FX bypass or record-disarm to apply to all tracks
TIP Right-click mute and solo for various options
TIP Alt+click IO button to enable/disable master/parent send
TIP Right+click FX button for quick-add menu
TIP Create multiple sends/receives:  select tracks, right-click IO button
TIP Shift+drag send knobs in extended mixer to adjust pan
TIP MIDI item volume and fade handles adjust note velocity
TIP Item pitch shift actions also transpose MIDI
TIP Edit tips.txt in the REAPER application directory to change what you see here
TIP JS plugins are 100% portable between Windows and OSX
TIP Create custom actions in the actions dialog to automate common tasks
TIP Use the plug-in pin connector for instant downmix or channel swap
TIP Right-click envelopes to interactively reduce automation points
TIP Tab key moves to next transient in selected items
TIP Save complex routing as a track template for reuse in other projects
TIP Shift+double-click to set the time selection to the selected item
TIP Double-clicking a track in the performance meter opens its FX chain
TIP Assign an action to a toolbar button and right-click the button to arm it for action
TIP Alt+drag envelope segments to adjust curvature
TIP Hold Alt while moving a fader, release Alt to keep the new level, release mouse to revert
TIP Right-click the track FX button to quickly add FX
TIP Sweep mute or solo: hold the button on one track, drag to the button on another track
TIP Hold the shift key while opening REAPER to start in safe mode (all FX offline)
TIP Reverse mousewheel zoom or scroll direction: reassign mousewheel in the actions window
TIP Use ReaControlMIDI to control track MIDI volume/pan
TIP Assign any plugin knob to the track control panel via the FX Param button
TIP Enable "trim content ... media when editing" to prevent overlapping media items
TIP Enable "trim content ... when recording" to prevent adding takes to existing items
TIP Right-click plugins in the Add-FX browser to mark plugins as buggy for special handling
TIP Control+shift+drag one side of a crossfade to temporarily toggle auto-crossfade behavior
TIP Right-click a fade-in/fade-out to change its shape, hold shift for crossfades
TIP Alt+click a fade-in/fade-out/crossfade to delete it
TIP Hold the control key in most cases to operate only on the current item, not all selected
TIP Control+alt+click mute/solo button to do exclusive mute/solo