diff -rupN --no-dereference OpenSceneGraph-OpenSceneGraph-3.6.5/examples/osgviewerWX/osgviewerWX.cpp OpenSceneGraph-OpenSceneGraph-3.6.5-new/examples/osgviewerWX/osgviewerWX.cpp

--- OpenSceneGraph-OpenSceneGraph-3.6.5/examples/osgviewerWX/osgviewerWX.cpp	2020-01-31 12:03:07.000000000 +0100

+++ OpenSceneGraph-OpenSceneGraph-3.6.5-new/examples/osgviewerWX/osgviewerWX.cpp	2021-11-13 21:34:02.963773980 +0100

@@ -91,6 +91,11 @@ bool wxOsgApp::OnInit()

     return true;

 }

+void __attribute__ ((constructor)) force_x11()

+{

+    setenv("GDK_BACKEND", "x11", 1);

+}

+

 IMPLEMENT_APP(wxOsgApp)

 BEGIN_EVENT_TABLE(MainFrame, wxFrame)