1. A system comprising: a processor; a memory; and a source code editor comprising at least one module loaded into the memory causing the processor to: receive program source code to be edited; generate an editor display using the program source code; trigger execution of extension code based on an occurrence of an event at the editor display, the event associated with the extension code, the extension code being distinct from the program source code to be edited, the extension code loaded from an external source into the source code editor and executable by the processor to determine that the editor display is to be modified and to generate a changed editor display upon determining by the extension code that the editor display is to be modified; and display the changed editor display generated by the execution of the extension code.