--- a/widget/gtk/gtk3drawing.cpp
+++ b/widget/gtk/gtk3drawing.cpp
@@ -1258,18 +1258,21 @@ static gint
 moz_gtk_arrow_paint(cairo_t *cr, GdkRectangle* rect,
                     GtkWidgetState* state,
                     GtkArrowType arrow_type, GtkTextDirection direction)
 {
     GdkRectangle arrow_rect;
     gdouble arrow_angle;
 
     if (direction == GTK_TEXT_DIR_RTL) {
-        arrow_type = (arrow_type == GTK_ARROW_LEFT) ?
-                         GTK_ARROW_RIGHT : GTK_ARROW_LEFT;
+        if (arrow_type == GTK_ARROW_LEFT) {
+            arrow_type = GTK_ARROW_RIGHT;
+        } else if (arrow_type == GTK_ARROW_RIGHT) {
+            arrow_type = GTK_ARROW_LEFT;
+        }
     }
     switch (arrow_type) {
     case GTK_ARROW_LEFT:
         arrow_angle = ARROW_LEFT;
         break;
     case GTK_ARROW_RIGHT:
         arrow_angle = ARROW_RIGHT;
         break;