Quick Answer: This feature is not supported in Liquid Notes.
Editing of chords in the piano rollLiquid Notes is a powerful tool for fast editing of harmony and melody of MIDI arrangements. For this purpose, MIDI events and chords are displayed in the user interface of the software with a set of three control elements per chord to make changes to your arrangement.
While MIDI events are shown in the piano roll, editing of chords is restricted to these control elements. No editing of chords directly in the piano roll is possible.