Maintaining a netlist while editing a circuit diagram. The circuit diagram may be displayed on a display. The circuit diagram may include a plurality of electronic components connected by nets and may also include modular block(s) which represent a circuit portion in a hierarchical fashion. A global netlist may be stored that includes information regarding the nets of the circuit diagram. User input may be received which modifies the circuit diagram. Accordingly, the global netlist may be updated in response to the user input modifying the circuit diagram. The circuit diagram may be updated on the display based on updating the global netlist. Receiving the user input and updating the global netlist and circuit diagram may be performed a plurality of times, in a dynamic fashion during edit time.