diff --git a/docs/Doxyfile.in b/docs/Doxyfile.in
index 81424bf6..0d3fb19d 100644
--- a/docs/Doxyfile.in
+++ b/docs/Doxyfile.in
@@ -240,7 +240,6 @@ DOT_IMAGE_FORMAT       = png
 DOT_PATH               =
 DOTFILE_DIRS           =
 MAX_DOT_GRAPH_DEPTH    = 1000
-DOT_TRANSPARENT        = NO
 DOT_MULTI_TARGETS      = NO
 GENERATE_LEGEND        = YES
 DOT_CLEANUP            = YES