I just came across a [question](https://stackoverflow.com/questions/14803649/explain-the-difference) where the question asker slightly modified his question but was not allowed to! Here's the [revision history](https://stackoverflow.com/posts/14803649/revisions). 

It was pointed out to the asker that one of his code segment doesn't compile and it makes no sense to ask difference between a compiling code and non-compiling code. I believe, this was the reason that question received 4 downvotes. (Otherwise, it's not such a bad question and wouldn't have received 4 downvotes IMO).

Asker edited the question saying:

> 
> Removed the first one which gave a compiler error. (My bad!)
> 
> 
> 

Asker's edit was rolled back with the reason:

> 
> I've rolled it back because all answers reference both example lines
>  of code; so they should both remain, regardless of their correctness.
> 
> 
> 

It's not that the asker changed the entire content of the question, he just modified an offending which part which accumulates downvotes for him and he did in quick time too (3-4 minutes).

Now the broader question, is it ok to not allow an asker change his/her question even if it changes the original context slightly and may make some (or part of) answers irrelevant? 

I have always thought it's the *answerer*'s responsibility to edit/delete the answer if the question has been modified and his answer became irrelevant. What's the consensus on this?