Avoid unnecessary GraphicsExpose events.

diff --git a/graphics/x11drv/bitmap.c b/graphics/x11drv/bitmap.c
index de17e60..c5323b8 100644
--- a/graphics/x11drv/bitmap.c
+++ b/graphics/x11drv/bitmap.c
@@ -112,6 +112,7 @@
     {
 	TSXFreeGC( display, physDev->gc );
 	physDev->gc = TSXCreateGC( display, physDev->drawable, 0, NULL );
+	TSXSetGraphicsExposures( display, physDev->gc, False );
 	dc->w.bitsPerPixel = bmp->bitmap.bmBitsPixel;
         DC_InitDC( dc );
     }