Kate scrollbars hidden

I try to get familiar with Kate, Version 18.12.3, under KDE, Version 
number unknown, under Leap 15.1. In the Kate Manual I read:

   Chapter 3. Working with the Kate Part editor
   ...
   The Scrollbars
      The scrollbars indicate the position of the visible part of the
      document text, and can be used to move around the document.
      Dragging the scrollbars will not cause the insertion cursor to
      be moved.  The scrollbars are displayed and hidden as required.

Unfortunately, the scrollbars (more than one?) are hidden, and there 
is no explanation how to display them.

Any help is welcome.

Thank you in advance and best regards,
Wolfgang