didEnterResponderChain behaviours
This fixes the following bug: when editing the number of significant
digits, input "1+", click on "OK", the data was reloaded and "1+"
disappeared...
Solve an equation that has solutions, select a solution, then go back
and change the equation. WHen you go to the solutions, the previous
solution is still selected, which is a little weird
Scenario: Go to the Result format submenu of Settings. Modify the
significant figures with a wrong value (for instance, "7::"), press OK
then 0 -> he first row is selected, as well as the last row