Column Headers (and their elements) don't get the focus to be keyboard usable.

[h.wagner@telekom.de]

Column headers (and their elements: sort, toggle, filter) don't seem to be able to get the focus .
This is more visible using something like:

*:focus {    border: 2px dotted #E20074 !important;} 

Because of this, accessibility users that are constrained to using the keyboard can't sort or filter ExtJS tables .
After clicking on the column dropdown icon , the column context menu appears and seems to be focusable, so usable with the keyboard to a degree, except:
- selection and focus are not in sync when toggling columns from the menu
- toggling columns also seems to freeze the menu for the keyboard navigation.

Thanks in advance.