Changes the values in the PropInfo-structure of a proportional
gadget and refreshes the specified number of gadgets beginning
at the proportional gadget. If numGad is 0 (zero), then no
refreshing is done.
INPUTS
gadget
Must be a PROPGADGET
window
The window which contains the gadget
requester
If the gadget has GTYP_REQGADGET set, this must be
non
NULL.
flags
New flags
horizPot
New value for the HorizPot field of the PropInfo
vertPot
New value for the VertPot field of the PropInfo
horizBody
New value for the HorizBody field of the PropInfo
vertBody
New value for the VertBody field of the PropInfo
numGad
How many gadgets to refresh. 0 means none (not even