Why did Oracle never create a When-Leave-Item/Record/Block/Form unrestricted trigger?

I need to clear a record if the fields on the screen are cleared associated with that record, by the user removing the value in the field.

I don't really want to use a timer to do this..., and also, my when-new-item-instance is huge already.  Is there not another way?

I need an unrestricted when-leave-item trigger.