It is also not possible to change a calculation if it is already set:
- create new tab control and enter a calculation.
- change to browse mode
- change to layout mode again
- open tab control editor window
- change the calculation of the last added tab control.
- save change
- close editor window and open it again…
- the first calculation re-appears…
ok, I think I always made a mistake:
It seems that I forgot to press the "rename" button always, using the OK-button only after changing the calculation.