Technically, you're dealing with two different phrases. Which one is correct depends on your usage of them, and in your two examples, both are equally correct.
When you insert a noun in between the two words ("all x but"), you are referring to a collection of x but noting that there are exceptions.
The "all but" idiom refers to the fact that the subject of the idiom is as close to being described by the adjective as it can be without being completely and accurately described by that adjective. Saying that the championship is "all but" decided is saying that, while it is not officially 'decided', it's so close to being decided that the distinction is hard to discern.
The key difference is that, if you replaced 'but' with 'except' in the first instance, it would still make sense:
Close all tabs except this one.
However, with the second instance, it is not considered a proper use:
The championship is all except decided.
The confusion exists because, sometimes, you can remove 'x' from the first use:
All but the oldest fruit was still edible.
How you can tell the difference here is that you can easily move the subject (fruit) between "all" and "but" and the sentence will still make sense:
All fruit but the oldest was still edible.
Also, as I mentioned before, either one of the last two examples makes sense when you replace "but" with "except", indicating that it is being used to imply the "all x but" descriptor.
The observation behind this question is very nice. Use of this locution in indeed limited, to perfect tenses:
- Present perfect: I have been to London to visit the Queen
- Past perfect (pluperfect): I had never been to London before you took me
- Future perfect: I will have been to London by the time you return
You can clearly imagine putting the phrase into other tenses. For instance, by analogy of I have been silly to I am (being) silly, you could form *I am to London, *I am being to London. Similarly, you expect *I was to London (I was silly) and *I will be to London (I will be silly). But none of these are possible.
Note 1. It is wrong to think of to have been as having have as a main verb. If so, one would expect the possibility of the past perfect have had been (comparing to, say, have had it coming), and this is clearly impossible.
Note 2. There is a (rather outmoded English?) idiom to have been, without any destination/location specified. It is a euphemism for going to the toilet. Monty Python made a recurrent joke out of it in a skit based around an Agatha-Christie-style murder (the reluctance to say murdered led to numerous characters asking simply Has he been ... ?, to which the others would answer something like Yes, before lunch).
Best Answer
According to Oxford Dictionaries the answer is yes they are interchangeable, but they also offer some style advice about word selection that indicates you might be better off chosing "Until."
(emphasis mine)