STEP SEQUENCER
The Graph Editor lets you set additional properties of notes in the Step Sequencer. You can set each note's panning (Pan), velocity (i.e. note's volume - Velocity), cutoff (Filter cut), resonance (Filter res), pitch (Pitch) and shifting (Shift). Shifting creates delay between the timing of a note event and the time it is actually triggered. 100% shift means one 16-th time delay. The pitch property sets note's pitch, but is more intended for use with drum channels and effects - if you want to enter a melody, use the Keyboard Editor instead.
Left-click a column and drag up/down to adjust the property. You can drag all values at once - hold Ctrl and adjust one, the others will follow. You can also create "lines" with values in the Graph Editor - right-click a value and drag to another, FL Studio will automatically interpolate the in-between values.
It is important that you understand in the Graph Editor you set note's properties - these are not separate events. So, although you can set all panning values, only those that correspond to active dots will be used.