dijit/focus registers a click in a scrollbar as a focus change

dijit/focus registers a click in a scrollbar as a focus change while the browser does not change focus.
As a result _onBlur is called when it should not, and more importantly, not called when it should be called.

Consider this scenario:
- I have a dijit/TextArea with intermediateChanges=false (the default)
- type some text in the textarea
- click on a scrollbar (any scrollbar) => dijit/focus considers this a focus change, thus calls _onBlur on widgets in the current stack and sets the new stack. The caret cursor though stays in the textarea.
- type some more text
- click anywhere outside the textarea => this is a focus change. The caret cursor disappears from the textarea. dijit/focus also registers it as a focus change, but since the active stack was already changed it will not call _onBlur on the textarea. The last text you entered is thus not set to the value of the textarea.

Found on dojo version 1.16.2