Fix #454
Fix the problem after following operations
 - Select several characters (in Visual mode)
 - Switch focus to another view in assistant editor by mouse click
 - Switch focus again to the previous text view (by Ctrl-w k or other window operation)
 - The view has selection but it works as if it is NORMAL mode.
Merge branch 'FixForcusProblem_#446' into Xcode5Support

* FixForcusProblem_#446:
  Fix the problem after following operations  - Select several characters (in Visual mode)  - Switch focus to another view in assistant editor by mouse click  - Switch focus again to the previous text view (by Ctrl-w k or other window operation)  - The view has selection but it works as if it is NORMAL mode.
  Fix #454