Need a little help with GtkLabel Markup

Hi folks. I'm working on fixing up the gnome-calculator display. Right now it
uses a GtkEntry and reverses the direction using gtk_widget_set_direction.
Obvioulsy this isn't right and it leads to quite a fex bugs. To get things
right I'm trying to get it working with GtkLabel using the markup capabilities.
Right now it works except I can't get the label to expand and right justify the
text at the same time. I've tried all sorts of packing options to no avail. The
problem is that I set the background of the label to a color, but since the
label doesn't expand only part of the display gets the background color.

I guess I could just set the background of the hbox, but is there a way to do
it without doing that. Attached is a screenshot.

Many thanks,

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