UPDATE | I\'ve uploaded a sample project using the panel and crashing here: http://w3style.co.uk/~d11wtq/BlocksCrash.tar.gz (I know the \"Choose...\" button does nothing, I\
Try defining your EDNewFilePanel with the __block
modifier:
__block EDNewFilePanel *newFilePanel = [EDNewFilePanel newFilePanel];
This should retain the object when the block is called, which may be after the Panel object is released. As an unrelated side-effect, this will make also make it mutable within the block scope.