set mesh.changed=1 after a Read_Mesh()

Mesh/Read_Mesh.cpp

-// $Id: Read_Mesh.cpp,v 1.75 2004-05-27 06:23:48 geuzaine Exp $
+// $Id: Read_Mesh.cpp,v 1.76 2004-05-31 01:54:19 geuzaine Exp $
 //
 // Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
 //
@@ -819,6 +819,8 @@ void Read_Mesh(Mesh * M, FILE * fp, char *filename, int type)
     return;
   }
 
+  CTX.mesh.changed = 1;
+
   if(filename){
     Msg(INFO, "Read mesh file '%s'", filename);
     Msg(STATUS2N, "Read '%s'", filename);