---++ Setting the new data into the window form

The loading process consists of seven steps.

   1. switch off the listeners
   1. unlock the actually displayed data record (if exists)
   1. loading the given (new) lecturer instance into the window form (if not null else initialize the elements)
   1. Check if the given record lecturer is already locked, i.e. it is already edited (if lecturer is not =null=, else enable the elements)
      1. YES: disable the form elements
      1. NO: enable them and lock the new record
   1. set member =input= to the new lecturer, =inputChanged= to true and enable next/prev buttons (if lecturer != =null= else...)
   1. set the window title
   1. switch on the listeners
   
---++ Closing Procedure

If a closing event occurs a listener proceed as follows. At first it checks if changes have been made:

    * YES: are the changes valid ?
        * YES: is a record displayed and did we locked it?
           * YES: release it
           * NO: 
        * NO: closing cancled
    * NO: is a record displayed and did we locked it?
        * YES: release it
        * NO: 