Why is the option for the Theis residual drawdown (recovery) method inactive (gray or dimmed) when I try to choose a confined aquifer solution?

AQTESOLV for Windows Knowledge Base

Select Edit | Pumping Well | Edit.
Click the Rates tab (v. 3.0+) or the Edit button (older versions) to verify that you have entered a recovery pumping period with the rate equal to 0.0 at the time when pumping stopped.
Select Edit | Obs. Well | Edit.
Click the Observations tab (v. 3.0+) or the Edit button to verify that your observation well data include residual drawdown measurements recorded after pumping stopped.