* helm-dabbrev.el (helm-dabbrev--same-major-mode-p): Fix inheritance in helm-dabbrev-major-mode-assoc.
* helm-dabbrev.el (helm-dabbrev): Assertion if nothing before point.
(helm-dabbrev--regexp): Add backquote.
* helm.el: Issue #282 #194 Don't allow switching out of minibuffer from
  helm session.
(helm-display-buffer): Add no-other-window property to all visible
windows.
(helm-frame-or-window-configuration): save no-other-window property too.