I wasn’t able to trace the precise change that did it, but at a certain point I had the peculiar problem of an OS X debug build crashing at startup, and hanging the IDE if I attempted to run it in the debugger. Switching to the ‘release’ build configuration allowed it to run, but when you’re working with a framework that is so, er, work-in-progress as FMX, not being able to run an application in the debugger for a certain target platform is rather debilitating.
Seeking to investigate the problem, I created a copy of the project and progressively removed units until it ran properly again. This led to things getting even weirder though, since use of generic types in unit initialization clauses or class constructors was seemingly the straw that broke the camel’s back! However, I finally hit upon a solution, which was to enable compiler optimisations (the default is ‘off’ in the stock debug configurations). To do this, I went to Project|Options, chose the second node down (Delphi Compiler -> Compiling), ensured ‘Debug configuration – OS X platform’ was selected in the combo box at the top, then ticked the ‘Optimization’ box and finally clicked OK.
Notwithstanding this issue, overall I’d say remote debugging in XE2 and XE3 from a Windows guest to an OS X host is pretty smooth (if a bit bumpy once exceptions get raised), so don’t let this put you off…
