diff --git a/src/guacenc/buffer.c b/src/guacenc/buffer.c
index f7387997..1a3481f9 100644
--- a/src/guacenc/buffer.c
+++ b/src/guacenc/buffer.c
@@ -100,8 +100,9 @@ int guacenc_buffer_resize(guacenc_buffer* buffer, int width, int height) {
 
     /* Copy old surface, if defined */
     if (buffer->surface != NULL) {
+        cairo_set_operator(cairo, CAIRO_OPERATOR_SOURCE);
         cairo_set_source_surface(cairo, buffer->surface, 0, 0);
-        cairo_rectangle(cairo, 0, 0, width, height);
+        cairo_set_operator(cairo, CAIRO_OPERATOR_OVER);
         cairo_paint(cairo);
     }