[glom/gtkmm4: 7/9] gtkmm4: Use property_margin() instead of set_border_width().

[Murray Cumming <murrayc src gnome org>]

commit 2d75a7b2453955d12430bc9437695afcb6fac67f
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Dec 16 16:45:27 2016 +0100

    gtkmm4: Use property_margin() instead of set_border_width().

 glom/window_boxholder.cc |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/glom/window_boxholder.cc b/glom/window_boxholder.cc
index a5c217f..72190c0 100644
--- a/glom/window_boxholder.cc
+++ b/glom/window_boxholder.cc
@@ -37,7 +37,7 @@ Window_BoxHolder::Window_BoxHolder(Box_WithButtons* pBox, const Glib::ustring& t
 
   pBox->signal_cancelled.connect(sigc::mem_fun(*this, &Window_BoxHolder::on_box_cancelled));
 
-  set_border_width(Utils::to_utype(UiUtils::DefaultSpacings::LARGE));
+  property_margin() = Utils::to_utype(UiUtils::DefaultSpacings::LARGE);
   add(*pBox);
 
   pBox->show();