Scrollbarview ensures host always focused. (#1486)

* Sets ScrollViewBar CanFocus to false to ensure the host always focused.

* Only navigates through TabView if winDialog is not null and ensures TextView being focused.

* Fixes both dynamic menu and status bar broken scenarios.

* Fix a bug where the subviews oldEnabled can be overridden, even the superview Enable property hasn't changed.

* Fixes CanFocus when set to false and HasFocus is true.

* Fixes the broken TextView DesiredCursorVisibility.