Fix regression on IE10 clicking blank screen to close drop down.
Fix regression on IE10 clicking blank screen to close drop down.

An e.preventDefault() call on MSPointerDown prevents the button from getting focus,
so I stopped doing it for that case.  This is a minimal fix.  Other approaches include:

  1. remove the e.preventDefault() call for all cases
  2. make focus manager listen for touch/mouse events in the capture phase rather than the
bubbling phase, to avoid missing the event due to a stopPropagation() call; it used
to do this except for IE6-8, but I normalized the behavior in 9965406.

Fixes #17262.  Refs #13048, #13341.
(cherry picked from commit 76216d6d829f011a87ccd11ee12d3a862d6e2e88)

harbalk/delite,Sam-Cummins/delite,harbalk/delite,kitsonk/delite,kitsonk/delite,Sam-Cummins/delite