It is already possible today. There are access control hooks provided via XACE. Nobody uses them because the attack scenario is basically non-existent. If you r

It is already possible today. There are access control hooks provided via XACE. Nobody uses them because the attack scenario is basically non-existent. If you run untrusted malicious apps having full access to your home directory you have big problems anyways. Not giving them access to e.g. the screen coordinates of their windows won't help you much then.