I went to Malaysia about 5 months ago and got a Multi Entry 12 month Non Imm "O" based on Marriage...last week i went back to malaysia to get my Buis Visa Non Imm "B", i was given a single entry 3 month B visa but they left my 1 year marriage visa in there and didnt stamp it out...when i re-entered thailand they asked which Visa d like to enter on...is this normal?

Why did you needed a non-B, you can get a WP on your non-O as well. I believe your non-O is now invalid, as you recieved a new visa and you can not have 2 at the same time. The consulat should have cancelled your non-O, but IMHO the non-O visa is now invalid anyway.

They should of canceled it at the embassy but it's not a problem.

Why did you go out and get a B your O is the same as a B. You don't have to change visas just because you wanted to get a work permit or even get an extension of stay for work.

Why you get a non-B?

You can get a work permit on your non-O.

It's just a different non immigrant visa.

I can not see why to change your visa status.

And you probably only get a single entry Non-B in Malaysia.

Why you need a non-B??

Agree with the above. Why you do? No need.

Getting divorced next week therefore had to come off "O" marriage visa

Your visa will still be good when you get divorced. It is just a regular non-o visa that was issued based upon marriage. It says no where on the visa it was based upon marriage.

Only an extension of stay would be canceled.

You may get different types of visas and even two visas of the same type (e.g you have been in Thailand for some months on a Non B, go out, decide to apply for a new one: when you are back to Thailand you just point out which one you want to use)

Therefore it is normal you are being asked that by an official

As said earlier: once you have been granted a visa you may come and go as long as it is valid