It was possible that when switching between tabs, and creating a
navigation history in one of the tabs, then switching tabs again, it
could clear out the individual tab stacks under certain scenarios.
Closes#1978
When a state change happens, ensure the keyboard is hidden. When a
keyboard is hidden, ensure all pending timers our cleared. When
resetting scrollView, ensure it’s only doing it when it has to.
For testing: #1670#2192
Instead of using pointer-events: none to disable unwanted clicks which
can cause flickering, we’re now using a click-block div that covers the
view during transitions. Similar concept to pointer-events: none
applied to the body tag, but in tests its showing to be more effective
to not cause any flickers.