Fix missing filters on query edit view.

app/controllers/queries_controller.rb

@@ -56,6 +56,7 @@ private
   end
 
   def prepare_for_editing
+    if request.post?
       @query.filters = {}
       @query.add_filters(params[:fields] || params[:f], params[:operators] || params[:op], params[:values] || params[:v]) if params[:fields] || params[:f]
       @query.attributes = params[:query]
@@ -65,6 +66,7 @@ private
       @query.column_names = params[:c] if params[:c]
       @query.column_names = nil if params[:default_columns]
     end
+  end
 
   def find_query
     @query = Query.find(params[:id])