For the small size ECOs, it is is not practical to resynthesize multi-million gates design to have only one inverter added. It's not a good practice either to use text editor to change million instances netlist. Normally, 85% of functional ECOs involve less than 20 gates. For those 85% small size or replicated ECOs, global mode Automatic ECO is over-killed and inefficient. GOF Debug gives users flexibilities to choose GUI and Script mode for those small size or replicated ECOs.
The following dynamic schematic shows how user can do ECO by mouse clicks.
Figure 1: GUI ECO
Check GUI Mode Neltist ECO/Debug for detail