So you mean you failed to unbind the Paste command? I just tried and it has no problem. Have you ensured you pressed the Backspace key once in the “Binding” field to clear it instead of just assigning the same hotkey to “override” it? When you click OK/Apply button in the Application Options dialog, if you see the “Binding” column of the Paste command is cleared as screenshot, you should be good to go.
I can prove that because I also tried to Google it before replying you, so I can just point you to existing resources if they are already available. The materials are in fact there but they seemed not very well indexed by the search engine.
But here’s a tip: to look for an option/setting/configuration, you can try search it either in the “Application Options” or “Project Options” dialog box. As their names suggest, they refer to the options that are global, and options that are project-specific respectively.
However, even for experienced VP user like me, it is often hard to determine whether an option is application scoped or project scoped, in such case I would first try find it in project options, and then the application options.
A rare exception is the “Customize UI” command, which lets you show/hide specific UI elements, and it isn’t in either dialog boxes but as a command on its own.