Occasionally a need presents itself that requires you to cut an access opening in a ceiling, next to a wall.
However, you don’t want the opening to be “OPEN” all the time, so you might build a panel to close over it.
Regardless of the type of panel, BEFORE you make a cut in the ceiling, MAKE CERTAIN that the ceiling is square with the wall. There are generally bulges in walls, some due to a twisted stud, perhaps a putty line or something else that keeps the wall, where the opening needs to be from being absolutely flat. So, if you are planning on having your access door swing down, perpendicular to the wall, there might be a problem with fitting it properly (especially against a stucco wall.
An easy remedy might be to hang the access door along the cut where the wall and ceiling meet, then swing the door down flat against the wall.
Remember, measure twice, cut once.