LPS-43212 Generating "redirect" parameter if one is not given; not giving a redirect when displaying edit screen in menu.

Also, creating another param ("backURL") for making clear when the portlet should display back URLs in headers. It should not be the case inside the popup
LPS-43212 "Add Calendar" screen should appear in pop-up, too, for consistency
LPS-43212 Reloading page after calendar addition, as is done on calendar deletion
LPS-43212 Using correct property name
LPS-43212 Removing "Save and continue" code: the calendar edit window should always get back to itself
LPS-43212 Preserving backURL when passed (e.g. through "Add Calendar" button)
LPS-43212 SF
LPS-43212 SF