There are two independent Report windows.
The first is to click on the Report folder and from the list of Reports shown in the tan table to the right, you can select any report which will show the accounts for the report in the window below.
The second is click the Report below the Tree Explorer on the left which will display the accounts in a blue table on the top right.
If you set the window in the First and then move away and go to the second, the window displays are independent of each other. Could this be your problem?