Fix to enable grip mode toggeling on page edit screen

Using modified code found in the thumbanils support thread here:
https://processwire.com/talk/topic/643-release-thumbnails/page-16#entry5
2117
Thanks go to user iNoize
Show .button-setfocus in Grid View
Merge branch 'admin-grid-view'

* admin-grid-view:
  Show .button-setfocus in Grid View
  Fix to enable grip mode toggeling on page edit screen