Canvas: clear elements in shutdown()

- without this change, elements aren't un-ref-ed and hence destroyed
until the actual dtor runs, which is too late (other systems may be
destroyed already)

diff --git a/simgear/props/PropertyBasedMgr.cxx b/simgear/props/PropertyBasedMgr.cxx
index 621d11db67efd2401ad43c049d22e59505917261..4091da9fa715c60b57681c218122e8981b183813 100644 (file)
--- a/simgear/props/PropertyBasedMgr.cxx
+++ b/simgear/props/PropertyBasedMgr.cxx
@@ -37,6 +37,7 @@ namespace simgear
   void PropertyBasedMgr::shutdown()
   {
     _props->removeChangeListener(this);
+    _elements.clear();
   }
 
   //----------------------------------------------------------------------------