Conditional formatting on a selected area only not working

I want to use conditional formatting only on a selected area within a pivot table.
When i select the area, then apply the conditional formatting, everything looks fine. At first…
But when i scroll around within the table, then suddenly with the first scroll action the conditional formatting is applied to the complete pivot table.
When i want to edit the conditional formatting in its dialog, it still shows the previously selected area which i wanted to format only.
Can i deactivate this “feature”?