I really wanted to find the solution to this problem on my own. But I already took some hours and have'nt found anything conclusive.

The thing is that whan editing a report and adding filter expressions I can't delete the only one remaining. What I mean is that I can add many filters and remove those filters one after another. Except for the last one remaining in the filters.

The other thing is that those filters added while in edit mode can be seen in the report wizard when the user wants to add his filters. The user should'nt be able to see those filters that were added in the edit mode. There's another thing. I can't remove the check that was made for "Use same filter the next time the report is executed"