FLStudio's Piano Roll nor do they support slide notes, these are exclusive to native FLStudio plugins. Note: If a VST plugin supports polyphonic aftertouch they can sometimes use the first per-note parameter in the Piano Roll ...
FLStudio 20.1.1 and VST3 instruments. If I play a note very softly, or manually set the velocity to 1% in the piano roll, the note is completely silent. This happens regardless of velocity routing inside the VST3 plugin itself ...