use head position predefined in operator variables, needed to properly select MWE ctags

libmwereader/mwe.cpp

@@ -65,6 +65,7 @@ bool LexicalUnit::IsHere(const Wccl::SentenceContext &sc,
 		return false;
 
 	bool found_head = false;
+	bool head_defined = false;
 
 	Wccl::SentenceContext sc2(sc.get_sentence_ptr());
 
@@ -81,12 +82,18 @@ bool LexicalUnit::IsHere(const Wccl::SentenceContext &sc,
 			out_position.insert( abs_pos );
 			if(!found_head){
 				sc2.set_position(abs_pos);
-				if(head_cond_->apply(sc2)->get_value()){
-					head_pos = abs_pos;
+				if(head_cond_->apply(sc2)->get_value()) {
+					if (!head_defined)
+						head_pos = abs_pos;
 					found_head = true;
 				}
 			}
 		}
+		if(boost::algorithm::starts_with(varname, "Head")) {
+			Wccl::Position predefined_head_pos = condition_->get<Wccl::Position>(varname);
+			head_pos = sc.get_abs_position(predefined_head_pos);
+			head_defined = true;
+		}
 	}
 
 	if(!found_head){