Bug#434646: libcurses-ui-perl: toogle destroys boolean value of Checkbox

[Willi Mann]

>> That said, I don't see any problem with applying your fix. The uncheck()
>> method "correctly" sets $this->{-checked} to 0, so people can't really
>> be relying on the empty string behaviour.
> 
> You can rely on its truth value. That's the way it should be used.
> 

Please tell that the DBI people. I discovered this problem when I passed 
the value that get() returns to DBI, for a boolean value field. It 
complained.

Willi