Am I right to think this should not have been allowed and that a new question should have been opened if the code was that different?
Yes; You were right to think that sort of edit is not supported.
I rolled that question back to its last form by the original poster. The new user edited it too drastically, in my opinion, by adding their own code and error; It could have been a very different issue, even with a minor, seemingly inconsequential change in the code.
The important part here is that the editor added in his own code; Not clarification of the OP's code, or bringing in the OP's code from somewhere else - but added his own code that he thought was directly related. Whether that code was, in fact, equal to the OP's or not is not the important point. The important point is that in order to maintain clear standards for editing, we don't generally permit this sort of modification. Because more often than not, the issues are going to be significantly different.
It is OK to edit someone's question to clarify language and the like, or add in code that you know is directly related (perhaps the OP had linked to a jsfiddle or some other resource), but not to just take over the question in that manner.
As the person who made the edit to the post I would like to explain why I did so.
Currently, I'm having the EXACT same issue that the Original poster with the EXACT same symptoms.
I found the current answer that was there was not accepted as the answer and it didn't have a single up vote on it. I pointed it out the poster that the answer was not helpful and he deleted the answer.
I went on to add a bounty to the question and started seeing some answers started showing up asking for more clarifying on the issue and slimmed down code so they can test it out for them self.
I created a small example and and edited the original post with the code and the error that I receive when this happens.
This is when this happened.
What I would like to clarify is that I never deleted anything from what the original poster has wrote, and that I have added a workable example of this issue so that it can tested by others. Yes the original poster did have some code there but it was snippets of his code and not a full working example.
What do you guys suggest? Should I start a new question? Will it get flagged as duplicate? If no then how can I clarify the original poster question?
Edit The question is now solved, please see this for the answer
Also to counter Andrew Barber argument about how my edit made such a dramatic different.
He argues that the original poster error is
and that is dramatically different then mine because I point out that the exception is
I'm not saying that my program is not crashing just like the original poster. What I'm saying is that my program is crashing and this is the exception that is being thrown before the program crash. The original poster did not say what his exception but I believe they are the same if you view my answer.
Second he claims that my code IS WAYYYYY different then the original poster, lets take a look:
Orginal Poster code
Anyone who has ever done any DirectX stuff can tell you that there is nothing different between his code and mine. They both achieve the same thing at the end. They find the matrix of location of the camera.