This override is no longer necessary. Removing it simplifies the AdvoLogix environment and provides a less complicated and native Lightning Experience.
To make these changes in lightning, navigate to the Object Manager in Setup and select Event. Under Buttons, Links, and Actions, the Edit and New Event buttons need to be edited to reflect the image below.
To make these changes in classic, navigate to Setup and type Event Buttons and Links into the Quick Find. From the side menu, click on Event Buttons and Links and edit the Edit and New Event buttons to reflect the image below.
This article only applies to organizations on version 1.68.0 and earlier.