プルダウン項目の 1 つを非表示にしたいのですが、サブセットを使用できません。また、最上位レベルは表示されたままにする必要があります。これを行う良い方法はありますか?
No, there is no way we can do it natively. If you don't want to use subsets I don't think there is any another way to pull it off
You can easily do this in New UX.
Go to Page designer mode->Context Selectors->Click on Ribbon/Settings button on Context Selector and use Hide/Show Feature.
In the classic UX you can use the decency, selective access, etc. as options as a driver as well.
In this case the best option is to create alternate hierarchy for such seletors and map it one to one via code reference for filtering. There is no built-in functionality such as @obriegr and @Misbah offered yet.
In this hierarchy you will have only the necessary levels.
That is not entirely true. You can theoretically create a line item that is formatted as text in the model, then drive access around that line item using find item and booleans for user access. This will allow you to POSSIBLY do this, but it will be a blank text entry, versus a dropdown or fill from entry process.You need around 4 supporting modules to make it work well, without making it so end users can get into areas their access should be limited in.