As you are constructing the topology of your application and you are dragging and dropping operators onto the Graphical Editor and connecting them, chances are that you often have to insert an operator in between two other operators that are already connected. One way to do that is to drop the new operator onto the Graphical Editor, then move the links to include the new operator. A more convenient way to do this is to drop the new operator on the connection between the two operators. The Graphical Editor will automatically add the operator and reconnect the connections.
Here I am dragging the Throttle operator and dropping it on the connection between the TradeQuote operator and the QuoteFilter operator. Notice that the connection between the two operators is highlighted during the drag, indicating that it will be the drop target.
After the drop, the Throttle operator is inserted between TradeQuote and QuoteFilter and the connections are adjusted accordingly.