1 files changed, 1 insertions, 1 deletions

diff --git a/src/window.h b/src/window.h
index 29e2565c0c8..1a6c02a309c 100644
--- a/src/window.h
+++ b/src/window.h
@@ -212,7 +212,7 @@ struct window
 #define WINDOW_RIGHT_MARGIN(W)                                              \
   (WINDOW_RIGHT_EDGE (W)                                                    \
    - (! FRAME_HAS_VERTICAL_SCROLL_BARS (XFRAME (WINDOW_FRAME (W)))          \
-      ? 1                                                                   \
+      ? ((WINDOW_RIGHTMOST_P (W)) ? 0 : 1)                                  \
       : FRAME_HAS_VERTICAL_SCROLL_BARS_ON_RIGHT (XFRAME (WINDOW_FRAME (W))) \
       ? FRAME_SCROLL_BAR_COLS (XFRAME (WINDOW_FRAME (W)))                   \
       : 0))