Open the Scale Curve Editor window of the new Path Deform modifier.

openPathDeformScaleCurve.ms

(
	fn collectButtons widget &buttons =
	(
		local children = widget.children()
		for i = 0 to children.count - 1 do
		(
			if children[i].__class__.__name__ == "QPushButton" do append buttons children[i]
			collectButtons children[i] &buttons
		)
	)

	local pathDef = modPanel.getCurrentObject()
	if isKindOf pathDef Path_Deform2 do
	(
		local QtWidgets = python.import "PySide2.QtWidgets"
		local iGlobal = (dotNetClass "Autodesk.Max.GlobalInterface").Instance
		local hWnd = (iGlobal.UtilGetCoreInterface16()).CommandPanelRollup.Hwnd
		local pushButtons = #()

		pathDef.scaleEnable = on
		windows.processPostedMessages()
		collectButtons (QtWidgets.QWidget.find (hWnd as IntegerPtr)) &pushButtons
		for button in pushButtons where button.text() == "Open Scale Curve Editor" do button.click()
	)
)