[gimp] app: keep error dialog above.

[Jehan <jehanp src gnome org>]

commit 2b75b63ab7e662a5feb22204e8523308caeb5c12
Author: Jehan <jehan girinstud io>
Date:   Thu Dec 17 22:21:24 2020 +0100

    app: keep error dialog above.
    
    In some cases, error dialogs may end up below other windows and stay
    unnoticed because of how dialogs are raised and hidden on various
    platforms. This is not very constructive. It's much better to make sure
    one sees an error when it happens (in some cases, it may mean possible
    data loss, so it should be at least acknowledged; also seeing it later
    may mean you can't know anymore which action triggered this error,
    making the whole process kind of meaningless and hard to debug).
    
    So anyway, let's make error messages prominent by having them always
    above.

 app/gui/gui-message.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/app/gui/gui-message.c b/app/gui/gui-message.c
index 3fc1495523..ef3762c3e2 100644
--- a/app/gui/gui-message.c
+++ b/app/gui/gui-message.c
@@ -410,6 +410,7 @@ gui_message_error_dialog (Gimp                *gimp,
 
   if (dialog)
     {
+      gtk_window_set_keep_above (GTK_WINDOW (dialog), TRUE);
       gimp_error_dialog_add (GIMP_ERROR_DIALOG (dialog),
                              gimp_get_message_icon_name (severity),
                              domain, message);