How do I disable Ctrl-W so it can be passed to the window?

[Michael Blight]

If I create an action for Ctrl-W and leave the action empty, it correctly does not close the tab like Ctrl-W normally would, but it doesn't pass the keystrokes to the underlying window. If instead I use a "synthesise input" action with Ctrl-W as the keystrokes, it goes back to closing the tab. 

[AutoControl support]

You can send the keystrokes to the webpage by selecting the "Send from the inside of webpage" option.