Comment 3 for bug 1011167

I tried working on this in the past and I remember that it was quite tricky to get right. There's a bunch of difficulty that comes from handling such exotic configurations, namely what happens when you have a situation where there is more than one edge for another perpendicular axis, for example

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There are two possible versions of each screen corner - which one should be the corner for the purposes of the corner actions?

Its probably fixable, its just going to take such a huge amount of time that I don't think I'll be the one doing it.