Link: http://sugarcrm.com

• Under custom/Extension/modules/[module to extend/modify]/Ext/Menus add a [new module].ext.php file with the additional menu options.
• If you want to change a menu option, loop through the menu array and replace that option with the new one, in the menu.ext.php file.
• Be sure to rebuild/repair the module before testing changes.
• Spend a good amount of time looking at the Sugar code as you’re working. It’s very powerful, and the less code you write, the better the solution will be.
• If you’re just modifying existing functionality, copy as much code as possible, the update it.
• Understand PHP classes and extensions.
• Never modify the distributed code.