Tab not as expected

[v0ltoz]

When using the examples you can tab your way through the elements on the screen, however, when you get to the date picker and space bar to open in (the Predefined ranges one) the next tab goes to the element below the date picker not the content inside the date picker. I would expect that seen as though the date picker is open the next tab should go inside the date picker. Also, the predefined ranges don't appear to be able to be used with the tab key which is a slight accessibility issue.

[luqin]

Welcome your PR