Change animated apps to double-buffered visuals by default.
diff --git a/progs/samples/overlay.c b/progs/samples/overlay.c
index 4542b49..23b5a47 100644
--- a/progs/samples/overlay.c
+++ b/progs/samples/overlay.c
@@ -326,7 +326,7 @@
 {
     GLint i;
 
-    doubleBuffer = GL_FALSE;
+    doubleBuffer = GL_TRUE;
 
     for (i = 1; i < argc; i++) {
 	if (strcmp(argv[i], "-sb") == 0) {