Common actions like forward and backward, or hotkeys can work fine through Parsec depending on how your mouse sends these events. Parsec is an elevated application that runs as system, so if your mouse is making use of an unelevated app to send these events, Parsec will not be able to accept it. Otherwise, it should work. Exceptions are:

• Media buttons - Parsec does not pass media buttons at this time, whether it comes from a mouse or a keyboard
• Other special events - Anything that isn’t a normal key press or mouse press, like interacting directly with Discord to mute it without using a hotkey, will not work
• Using these on macOS hosts - Unlike Windows hosts, macOS hosts have trouble with simple mouse button actions like going forward and backward