MetarProperties: don't double-trigger listeners on invalidate

diff --git a/src/Environment/metarproperties.cxx b/src/Environment/metarproperties.cxx
index 97b94da0a8ae940f56ad1e6df287a1cc8c337489..1ebdd33b0da805cc6f8ad59ea6513560b7fca24b 100644 (file)
--- a/src/Environment/metarproperties.cxx
+++ b/src/Environment/metarproperties.cxx
@@ -192,7 +192,8 @@ MetarProperties::~MetarProperties()
 
 void MetarProperties::invalidate()
 {
-  _metarValidNode->setBoolValue(false);
+  if( _metarValidNode->getBoolValue() )
+    _metarValidNode->setBoolValue(false);
 }
 
 static const double thickness_value[] = { 0, 65, 600, 750, 1000 };