That overlay modes can use to access the underlying token info.

Since it produces orderings that don't correspond to what
the browser does then.

To take document direction into account

Closes #4878.

Issue #4926

Closes #4975. Checking `hasFocus` is a reasonable idea, but in Firefox
`hasFocus` returns false on `mousedown` if the window, but not the document
was focussed before. This leads to a wrong cursor in `contenteditable`
input style.

To avoid unpredictable selection behavior depending on whether the
mouse drag started a pixel to the left or right of the boundary.

Issue #4926

Issue #4926

Issue #4926

As @afercia points out, this use of aria-label makes no sense.

Issue #4958

This reverts commit bde68f12.

Issue #4958

Issue #4926

Issue #4889

Modern browsers handle updates to a textarea's value fast enough
to not do this anymore.

Issue #2703

Closes #4840

Issue #4840

This way, only one char's left and right edges are used, instead of its
(logical) neighbour's right edges.

In bidi content, this avoids trying to scroll to two logically close,
but visually far apart positions in some situations.