When changing either the date or amount of occurrences after which the repeating stops, the radio button should be selected automatically to the appropriate setting. Example follows.

The defaults:

Stop Repeating
(x) After _#_ occurrences
     Date
( ) [                  ]

The user then clicks the date input field and adds a date. What the user gets is:

Stop Repeating
(x) After _#_ occurrences
     Date
( ) [01.01.2012]

What the user should get is:

Stop Repeating
( ) After _#_ occurrences
     Date
(x) [01.01.2012]

And vice versa: when the radio button for date is checked and the user changes the amount of occurrences to any number bigger than zero, the occurrence radio button should be auto-checked. Saving nearly every user of Date Repeat a click nearly every time they add or modify an event amounts to a substantial improvement in aggregate user experience every day.