open Acrobat with "Page and page panel" by default

Have you looked at the "Initial View" of the PDF's docuemnt properties for a given PDF or for all PDF you can edit the Acrobat/Reader preferences to force all PDFs that do not have an intial view set, to open with either navibation pane visible.

Thank you very much for the hints. For a single document it is not a problem to find the option "page and page panel" in the properties. But for all of the documents I cannot find, where to set this option in the preferencies. Maybe I am too blind.

From Acrobat/Reader's menu bar, select 'Edit => Preferences", select the "Page Display" category and select the "Page Display:" form the drop down list. Note versions before 6 do not have this option.

Thank you for your help.
Unfortunately there is no option to set the default view "page and page panel" or "page and bookmarks", like it is possible on a single document. To set the layout is possible, but not the view.
(Maybe it is necessary to write a javascript. But sorry I cannot)
Thank you anyway. Regards from Austria.