[regression]Date picker cell with Datagrid

[Eric Pasquier]

A simple double click doesn't open the Date picker in a Datagrid cell anymore. Instead, you get an empty combo box, and you have to click one more time to open the Date picker.

[evan]

(In [23651]) Fixes #12195, font color shouldn't be #fff which makes text box or other editable widgets look like empty.

[evan]

Caused by soria theme, when row over the Date Text Box, the font color is changed to white and this make the widget look like empty.

With the fix now the behavior of testdate3.htm is the same as ​test_edit_dijit.html

[Eric Pasquier]

Thanks for the fix ! It is easier to understand the use of the new dropdown button. To be complete, I also tested claro and nihilo themes, as test_edit_dijit.html is using tundra, and they are working correctly (but you may have done the same tests).