Calling clear or setValue(null) on DateBox throws a NPE.

[FrankHossfeld]

To reproduce the error, create a DateBox using this code:

    myDateBox = DateBox.create("myDateBox"))
        .setReadOnly(true)   
        .setPattern("dd.MM.yyyy")
        .setParseStrict(true)
        .withPopover((parent, popover) -> popover.addCss(dui_accent_blue));

and then call:

myDateBox.clear();

or

myDateBox.setValue(null);

this will create the following issue:

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This happens in version 2.0.0-rc1. In version 1.0.0 it works as expected.