I create a split form for my database. As usual, my split form consists of the datasheet part and the form part. When I right clicked the datasheet part, some option like "Sort A to Z", "Sort Z to A", "Field Width", "Hide Field" and etc will appear. I want to disable this right click function. Is it possible?

I'm curious as to why? One of the main advantages of a split form is to let the user use those functions to find the record they want. But you can disable context menus in Options.

Actually, I hide certain fields and I don't want the user to have the capability to unhide the fields. I tried to disable context menus in Options, but it seems that I have no idea how to actually disable it.

I assume you want to hide the columns on the form part as well. So just delete the controls from the form.