MahApps/MahApps.Metro — pull request #1608 by thoemmi (2014-10-25 15:49:32+00:00)
Title: Double focus in NumericUpDown control

If you use the keyboard to navigate through the controls, `NumericUpDown` will receice the focus twice: first the entire control, and the second focus goes to the actual text box. I fixed it by applying `Focusable="false"` in `NumericUpDown`'s control template.