[four-in-a-row/arnaudb/wip/gtk4: 83/92] Try a fix.

[Arnaud B. <arnaudb src gnome org>]

commit 51fcbc4d90b674adffe9bf821050d6ec157d1521
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Sun Apr 19 23:33:53 2020 +0200

    Try a fix.

 src/game-window.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/game-window.vala b/src/game-window.vala
index f505f8c..114aa21 100644
--- a/src/game-window.vala
+++ b/src/game-window.vala
@@ -407,7 +407,7 @@ private class GameWindow : AdaptativeWindow, AdaptativeWidget
 
         game_finished = false;
 
-        if (!back_button.is_focus)
+        if (!back_button.is_focus ())
             view.grab_focus();
      // redo_action.set_enabled (true);
         undo ();