Setting multiline TextCtrl background color for entire width of control.

Hello again,

I have a multiline wx.TextCtrl widget for which I'm trying to set the
background color line-by-line. I'd like the background color to to
extend the full width of the control, not just the width of the text.
I've tried using wx.TextCtrl.SetStyle, but it only seems to affect the
background of text. From the image included with the following post:

http://lists.wxwidgets.org/archive/wx-users/msg64112.html

it seems as if this should be possible, but I can't find out exactly
how. I suppose I could pad the end of each line of text with a lot of
white space and hope the TextCtrl width never exceeds the width of
such a padded line of text, but I'd rather avoid such a kludge. I'm
running wxPython 2.5.3.2 on Ubuntu (Hoary) with Python 2.4.1, although
I think I have the same problem under Windows XP. Any suggestions?
While we're at it, is there a way to determine the width (in
characters) of a TextCtrl?

Thanks,
C.D.