retval, trackID, _, fx = reaper.GetFocusedFX()
if retval == 1 then
tr = reaper.CSurf_TrackFromID( trackID, false )
if tr then
param = reaper.TrackFX_GetNumParams( tr, fx ) -1
val = reaper.TrackFX_GetParam( tr, fx , param)
reaper.TrackFX_SetParam( tr, fx , param...