Selecting multiple files causes strange behaviour

[Clownacy]

For now, I've worked around this in 2fb4468, but I want a real fix. For whatever reason, whenever you select a bunch of files, and try (de)compressing them, Windows calls InvokeCommand with the wrong command ID.

What triggers it is having two options with the same name. Yes this happens even if the two options are in separate submenus.

And this only happens when a bunch of files are selected. It has something to do with that dumb change Microsoft made in Window 7(?) where QueryContextMenu is called twice when more than 16(?) files are selected, the first call clamping the file count to 16, and the second call using the real number.

Also see sonicretro/KENSSharp#3.