For editing: Hold down open and then press the palette... Now edit like normal and update. Or select some fixtures, select the palette, edit the values, record, GLOBAL, select the same palette and merge, or directly merge.
Same for knockout, open the palette, knockout the parameter, update
example: i open a global color palette with seeing just one line named "All" then it is not possible for me to change color values with the "set-key". is this normal behavior ?
