applyPriorityResizeFromOldSize: can incorrectly skip height resizing on certain views

[chrismcs]

High level overview of the bug: You're using a dictionary for priorityIndexes, so you effectively loose sight of view indexes if you have 2 or more subviews set to the same priority.

Here was my specific scenario: I have a vertical DMSplitView with 3 subviews. I want the middle subview to be resized when the window is resized, but I'd like the outer subviews to stay at a fixed size (unless they are manually resized).

So in my setup, I had the following priorities set for my subviews: subview 0: 490 subview 1: 1 subview 2: 490

Because priorityIndexes uses priority as the key, it lost sight of subview 0 (because when I made the call to setPriority: 490 ofSubviewIndex: 2, that overwrote the entry in the dictionary for subview 0.

The main problem this created was that subview 0 would no longer get vertically resized because subview 0 wasn't in the priorityIndexes dictionary anymore.

The obvious workaround for my case was to simply set subview 2's priority to 489 and now it resizes as expected.