[gimp] app: fix gimp_single_window_strategy_show_dockable_dialog()…

[Jehan <jehanp src gnome org>]

commit 1984ebf7162b5ac9579dd5fe882b427a10645292
Author: Jehan <jehan girinstud io>
Date:   Sat Mar 5 15:33:12 2022 +0100

    app: fix gimp_single_window_strategy_show_dockable_dialog()…
    
    … in specific case when there is already a toolbox.
    
    Even if there is already a toolbox in single window mode (hence it needs
    neither to be created nor raised, as there is a single window), we still
    want to return the dockable widget which can be used for other things.

 app/display/gimpsinglewindowstrategy.c | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/app/display/gimpsinglewindowstrategy.c b/app/display/gimpsinglewindowstrategy.c
index 7d0ab93d48..979c7785de 100644
--- a/app/display/gimpsinglewindowstrategy.c
+++ b/app/display/gimpsinglewindowstrategy.c
@@ -107,6 +107,10 @@ gimp_single_window_strategy_show_dockable_dialog (GimpWindowStrategy *strategy,
                                       GIMP_DOCK (widget),
                                       -1 /*index*/);
         }
+      else
+        {
+          widget = gimp_dialog_factory_find_widget (factory, "gimp-toolbox");
+        }
     }
   else if (gimp_dialog_factory_find_widget (factory, identifiers))
     {