Perhaps in my original post(s) on this topic, I should not have generalized as to which apps I was talking about. I meant to refer only to Messages. I used to want it to open it at Login, but now I no longer want that.
To investigate coordination between the list of Login Items and the Open at Login option in the Dock, I conducted 2 tests.
In my first test:
1. I opened System Preferences==>Current Users Login Items. Messages was not even in the list.
2. I quit out of System Preferences.
3. I went to the Dock and right clicked on Messages==>Options and selected Open at Login so now there is a checkmark next to Open at Login.
4. I opened System Preferences==>Current User’s Login Items again. Messages WAS now in the list, but the box to the left of it DID NOT HAVE A CHECKMARK. To me, this means the coordination between Login Items and Dock Options is not functioning completely. I should have seen Message in the list AND a checkmark next to it.
5. I quit out of System Preferences.
6. I went to the Dock and right clicked on Messages==>Options again and DE-selected Open at Login so now there is NO checkmark next to Open at Login.
7. I opened System Preferences==>Current User’s Login Items again. Messages was NO LONGER IN THE LIST at all. I think removing Messages from the list entirely was overkill. Instead, it might more properly have remained in the list, but without a checkmark.
In my second test:
1. I opened System Preferences==>Current Users Login Items. Messages was not even in the list.
2. I quit out of System Preferences.
3. I went to the Dock and right clicked on Messages==>Options and selected Open at Login so now there is a checkmark next to Open at Login.
4. I opened System Preferences==>Current User’s Login Items again. Messages WAS now in the list, but the box to the left of it DID NOT HAVE A CHECKMARK.
5. I put a checkmark in the box.
6. I quit out of System Preferences.
7. I went to the Dock and right clicked on Messages==>Options again and saw that there was still a checkmark next to Open at Login.
8. I opened System Preferences==>Current User’s Login Items again. Messages was still in the list with its checkmark checked.
9. I UNCHECKED the box next to Messages.
10. I quit out of System Preferences.
3. I went to the Dock and right clicked on Messages==>Options and there is STILL a checkmark next to Open at Login. (To me, this means the coordination between Login Items and Dock Options does not function properly.)