Selection and focusing cells broken in native editor

[DonJayamanne]

Master branch
Creating a single issue as they seem to be related.

Selection issue

• Open a native editor with at least 3 cells
• Select the first cell (click to select)
• Next, select the second cell (click the second cell).
  Bug: Both first and second cells are selected

Focus & Selection issue

• Open a native editor with at least 3 cells
• Select the first cell (click to select)
• Next, set focus to the code (click editor in cell)
• Confirm style has changed to indicate cell is not selected but focused
• Now try to click the cell to select it, selection no longer works.
  Bug: selection no longer works.

Focus issue

• Open a native editor with at least 3 cells
• Next, set focus to the code in the first cell
• Confirm style has changed to indicate cell is not selected but focused
• Now try to set focus to the editor in the second cell
  Bug: First and second cell have the style of focused.

Cell navigation using arrow keys and focus on code

• Open a native editor with at least 3 cells (one line each in the editor)
• Set focus to the editor in the first cell
• Press the down arrow
• Focus moves to the second cell, however the focus is NOT on the editor of the second cell.
  Bug: Focus does not remain in the editors
  (previously when using arrow keys, the editors in each cell would still have focus)

[rchiodo]

Selection isn't supposed to be clickable.

Now try to click the cell to select it, selection no longer works.
Bug: selection no longer works.

The other ones are bugs.

[IanMatthewHuff]

Validated