Unfortunately, the OSX editor has a few problems with stability, which are present in varied parts of the program. For me, I have had inexplicable crashes occur in the Events editor, the Map editor and the NPC editor. However, aside from the Map editor problems, the Events and NPC crashes have not been repeated. Also, in the Map editor, when placing stamps in Layers mode, the outline box that appears in the Classic editor does not appear, making Map production a hit-and-miss proposition.
For the moment, I reluctantly recommend doing your map work in the Classic editor (it's easier with floating palettes too) and the rest in the OSX editor, which seems a bit faster for me in other areas. When a patch appears, hopefully it'll add stability and the outlines box to the OSX editor, but until then, Classic might be the only option.
-Andiyar
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"Any good that I may do here, let me do now, for I may not pass this way again"