DropDownButton Enter and Space keys broken in IE8

[haysmark]

See:

​http://archive.dojotoolkit.org/nightly/checkout/dijit/tests/form/robot/Button_a11y.html

In IE8, you should get 4 test failures, in the tests related to the space and enter keys. Indeed, when you tab over to the Edit button and press either Space or Tab in FF, the menu appears, but in IE8, nothing happens.

[bill]

Hmm, too bad, this was broken in [21895] but I thought I had handled the issue in [21892]. I'll take another look.

[bill]

(In [21981]) Refactoring code to make opening from DropDownButton via keyboard (space/enter key) work on IE8:

• make _HasDropDown setup handlers on the focusNode, rather than domNode (simply by removing _buttonNode attach point), so that those handlers are isolated from the hidden <input> (which also fires a click event), and so the handlers still fire even though the ondijitclick code does a evt.preventDefault()
• connect to onkeydown rather than onkeypress since the ondijitclick's evt.preventDefault() call (in the onkeydown handler) cancels the onkeypress event on IE8.

Fixes #11040, refs #11003.

[bill]

(In [22001]) Second try to fix drop down menu opening via ENTER/SPACE key. Refactoring of _Has

• Switched keyboard handling to onkeyup so that drop down doesn't receive spurious keyup event.
• Separated keyboard and mouse handling into separate functions that don't call each other.
• Since _HasDropDown monitors mousedown and mouseup explicitly (and also keyup), it didn't seem necessary to connect to the onclick event at all. That invalidates the _stopClickEvents flag; hopefully that doesn't break anything. FilePickerTextBox? still seems to work and so does DropDownButton/ComboButton?.

Refs #11040

[bill]

(In [22010]) Not all drop downs (notably TooltipDialog) have a focus method. Refs #11040 !strict.

[bill]

(In [22120]) [22001] shouldn't have removed the stopEvent() call on click, refs #11040