better fix for #13

Author: slarosa

select_by_relationship_plugin.py

@@ -51,6 +51,8 @@ def __init__(self, iface):
         self.iface = iface
         self.sFr = None
 
+        self.iface.newProjectCreated.connect(self.resetRelation)
+
         self.actions = []
         self.menu = self.tr(u'&Select by relationship')
         self.toolbar = self.iface.addToolBar(u'SelectByRelationship')
@@ -188,6 +190,12 @@ def unload(self):
             self.sFr.disable()
             del self.sFr
 
+    def resetRelation(self):
+        if self.sFr:
+            self.sFr.relationsChecked = {}
+        self.comboRelations._checkedItems = set()
+        self.comboRelations.setCheckedItems(set())
+
     def populateComboRelations(self):
         self.comboRelations.clear()
         relations = self.sFr.manager.relations().keys()