Prevent widgets from being undrawn on resize?

[Benjamin Kimock]

I'm working on an application that is intended to be used over X11 forwarding, so drawing is a significant bottleneck. In most places I've been able to draw only what pixels have changed, except if the window is resized in which case I'm forced to draw everything.

I suspect the culprit is a call to 

XDestroyRegion()

in

Fl_Widget::damage(uchar

(which lives in Fl.cxx)

but I can't figure out what to do about it. I feel like there should be some method I can override but so far none I've tried have helped. Any suggestions?