I have developed a custom VF page for manipulating Opportunity Product sObject in addition to default page, which is also being used. I want to be able to fire after update trigger only if update to the record is originating from default page. I have created a custom field on the object that keeps track of the originating page but I'm not sure how to enforce setting field value when the update is originating from default page. Perhaps there is a better way for controlling the logic? Thanks

I have developed a custom VF page for manipulating Opportunity Product sObject in addition to default page, which is also being used. I want to be able to fire after update trigger only if update to the record is originating from default page. I have created a custom field on the object that keeps track of the originating page but I'm not sure how to enforce setting field value when the update is originating from default page. Perhaps there is a better way for controlling the logic? Thanks