small fix in join paths

extensions/fablabchemnitz_join_paths_optimized.py

@@ -131,6 +131,7 @@ class JoinPathsOptimEffect(inkex.Effect):
                 parts = paths[key]
                 # ~ parts = getPartsFromCubicSuper(cspath)
                 start = parts[0][0][0]
+                try:
                     elem = self.svg.selected[key]
 			
                     if(len(newParts) == 0):
@@ -150,6 +151,8 @@ class JoinPathsOptimEffect(inkex.Effect):
                     parent = elem.getparent()
                     idx = parent.index(elem)
                     parent.remove(elem)
+                except:
+                    pass #elem might come from group item - in this case we need to ignore it
 					
             newElem = copy.copy(firstElem)
             oldId = firstElem.get('id')