CreateBitmap can take nHeight or nWidth = zero, and then returns a
pointer to a 1x1 monochrome bitmap.

objects/bitmap.c

diff --git a/objects/bitmap.c b/objects/bitmap.c
index c12c663..80dc0a2 100644
--- a/objects/bitmap.c
+++ b/objects/bitmap.c
@@ -110,7 +110,13 @@
 
 
       /* Check parameters */
-    if (!height || !width) return 0;
+    if (!height || !width)
+    {
+        height = 1;
+        width  = 1;
+        planes = 1;
+        bpp    = 1;
+    }
     if (planes != 1) {
         FIXME("planes = %d\n", planes);
 	return 0;