How do I deactivate the dialog that appears when you hold a number key pressed?
You need re-enable key repeat for this context menu to go away. It'll affect character keys as well as number keys.


Open Terminal.app
Enter the following to turn this context menu feature off and reenable the old key repeat behaviour: defaults write -g ApplePressAndHoldEnabled -bool false


And you're done. Holding down any key now should repeat that key in the text entry window instead of calling up that context menu to select alternate characters.

To turn the context menu feature back on enter: defaults write -g ApplePressAndHoldEnabled -bool true instead.