Use update rather than show in focusable node re-render

Update checks if there's actually a context menu to show. We also need
to pass through the parameters for show.

This was causing the last-shown context menu to appears after resizing
an inline image (which has no context menu).

Change-Id: I8f46f71e2fba6896fe10054f0d2a679c6f23eb9c
Merge "Use update rather than show in focusable node re-render"