design of radio-button choice

[Sarah Reichelt]

>> Thanks -- and to Alex, too -- I hadn't thought of grouping the  
>> check- boxes. I'm first going to try a simpler & more permissive  
>> approach  and see how the user-experience feels, but if that's not  
>> satisfactory  I'll do the second group.
>>
>>
> That's (kind of) why I suggested a global rather than disabling the  
> check boxes.
>
> There's a danger of the user seeing those click boxes and being  
> frustrated by the fact that he wants to click one of them (to move  
> on to the next question?) and isn't allowed to. That's how *I* feel  
> sometimes about UIs - even if the UI guidelines say you should  
> disable controls that aren't available.   So I thought that my

I find it frustrating to come across a disabled button and not be  
able to see why it is disabled. In one application I am developing, I  
have adopted the following strategy for screens where a lot of data  
must be entered before proceeding: I put an invisible button  
underneath the disabled button. If the disabled button is clicked,  
the click passes through to the button underneath which can tell the  
user what data is missing. This saves people a lot of time trying to  
work out why the button is disabled, while giving them the visual  
feedback that they haven't finished. If the button is enabled, it  
traps the click and the information button underneath never gets used.

I'm sure the HIG purists will be horrified at this, but for this  
particular app, it works really well :-)

Cheers,
Sarah