diff --git a/src/servers/app/BitmapManager.cpp b/src/servers/app/BitmapManager.cpp
index 68ee91aa98..fde062affd 100644
--- a/src/servers/app/BitmapManager.cpp
+++ b/src/servers/app/BitmapManager.cpp
@@ -120,8 +120,12 @@ if (flags & B_BITMAP_WILL_OVERLAY)
 		bitmap->fInitialized = true;
 
 		if (flags & B_BITMAP_CLEAR_TO_WHITE) {
-			// should work for most colorspaces
-			memset(bitmap->Bits(), 255, bitmap->BitsLength());
+			if (space == B_CMAP8)
+				// "255" is the "transparent magic" index for B_CMAP8 bitmaps
+				memset(bitmap->Bits(), 65, bitmap->BitsLength());
+			else
+				// should work for most colorspaces
+				memset(bitmap->Bits(), 255, bitmap->BitsLength());
 		}
 	} else {
 		// Allocation failed for buffer or bitmap list