How to change the background color for tix.Balloon message?

I've been pulling my hair out for this one...

I've configured my tkinter app to use tix, so that I can leverage the Balloon widget for tooltips. However, the balloonmsg that pops up is a very hideous yellow, and for the life of me I can't figure out how to set the background color. Here's what I've tried so far:

b = tix.Balloon(self, statusbar=self.status,bg='grey87',initwait=500)
b.subwidget('label')['bg'] = 'grey87'
b.subwidget('message')['bg'] = 'grey87'

This config has only resulted in this:

I've found a way that works, although maybe not an ideal solution:

b=Tix.Balloon(master,statusbar=statusbar)
for sub in b.subwidgets_all():
  sub.config(bg='grey')