In immigration, display caution that don’t use phone, don’t use camera. So, better way is printing paper because some people in immigration are old books
Cambodia is a county that don’t concern applicant’s information too much. So, You can get it.
But if you will entrance to Thailand , don’t show DTV first. You should entrance with ED re-entry. If they suspect you hold two visa. They can reject visa.
One person should have one visa at a time. It is their rule. If you want one and you must cancel previous one.
At the beginning time of changing Evisa system, they don’t request Visa history of the application.
Most application apply DTV without cancelling the previous Visa because Evisa is an external paper. If you wil not show DTV E-Visa in immigration, they will not stamp DTV.
But Now
Thai embassy in Vietnam, I heard if you have before visa, they ask why the reason of that cancellation visa. They will also request all visa page in your passport.