Here's an interesting scenario:
A question was closed as off-topic. I voted to reopen it and it was eventually reopened. However, in the process of getting reopened the question was edited. I closed the edited question as a duplicate of a different question, and another user reopened it (both of us have gold tag badges). The question was then rolled back several times, until it was back in the form that had been closed as off-topic.
At this point someone voted to close it again as off-topic, and here's where it gets interesting. Normally, once you vote to close a question and it gets closed, or you vote to reopen a question and it gets reopened, you can no longer cast that same vote. Since I had already voted to close this question (as a duplicate) I no longer had the ability to cast a vote to close it as off-topic. However, I was also prevented from voting to leave it open as not off-topic.
Why am I unable to vote to leave this question open? I can think of two possible reasons:
- I already voted to close it and it was closed.
- I already voted to reopen it and it was reopened.
Yet neither of these reasons seem so logical. I voted to close the question for a different reason, so why should I not be able to vote that the current reason does not apply? (I suppose this could be tested by finding a case where someone voted to close and the question was closed and then it was reopened by other users and then sent to the Close Queue for a different reason.) If I can even vote to actually reopen a question that I have participated in closing, I should a fortiori be able to merely vote to leave open a question I participated in closing.
And if it's because I reopened the question, why should I lose my leave open vote? In general, when you are involved in closing or reopening a question you can still vote to leave the question the way it is if it comes up in the queue again. So the fact that my reopen vote succeeded should not be a reason for me to lose my leave open vote.
And if neither one of the above factors is a good reason for me to lose my leave open vote then the combination of them should also not remove my ability to vote.