Mike and Florin, thanks for looking into this. Even I am not a very experienced programmer I did some debugging this morning. I have entered a few lines of code in the refresh method and in the release method - and also in the find_by_lpor, the lpor, and the constructor method. And finally in the method called from the task.
Here are my findings for an instance background method:
First find_by_lpor is called - and from this if no instance is available in the table of instances, the contructor is called.
Then the method of the task - after this, the lpor method a lot of times. From 6 to 38 times actually...
Then the refresh method even I have not coded any calls to this myself.
And finally the lpor method again several times.
The refresh method is called from FM SWF_UTL_INVOKE_CLIF_METHOD line 311.
A dialog method is called the same way - here I'm also forced into the refresh method at the end.
The release method is never called by the system itself as it is with the refresh method.
Great if you guys can end up with some kind of conclusion which type of code should be entered in the refresh method then for future reference 
.
Thanks again,
Claus.
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