diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 6628a90100..1faadd14a3 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -4342,7 +4342,7 @@ colorswatch {
   }
 
   &#add-color-button {
-    border-radius: $_colorswatch_radius $_colorswatch_radius 0 0;
+    border-radius: $_colorswatch_radius 0 0 $_colorswatch_radius;
 
     &:only-child { border-radius: $_colorswatch_radius; }