When manually entering dates, typing '0' in month or day section resets the text to the placeholder.

Normally when entering a number, the focus shifts to the next field when the required digits are entered. For example, entering '10' for the day section, moves focus to the month. 
When we need a date where day < 10 however, we need to tab or enter the date separator to switch to the next part.

Allowing 0 in the dates should improve the users speed for entering dates and create a more unform behaviour.

Currently situation:
Date: 10/12/2017 => user input: 10122017
Date: 01/01/2017 => user input: 1/1/2017

When allowing 0 the last date can be entered as 01012017