If you were to glue a penny, across two keys.
And have one as IWT, the other as your DPS key.
Pushing the penny would be one action on your part, but two keys would be pushed.
As far as the game is concerned, it is two inputs; one on key push down and another on key release.

If Blizzard did not want us to do this, they would not have put that functionality into the game. If they decide to not allow this, it is simple on their part -- just remove the functionality which they have given us.

Quote Originally Posted by Ualaa View Post
Click on the Keymap name (DPS 1, for example). Change, "Execute a Step when the Hotkey is" from "released (Default)" to "Pressed or Released".
If you don't want to do this as a single keystroke, omit this one step.
Spam the key twice as fast, first press is IWT and second press is your hotkey.