#83 unsafeDefaultItem does not work permanently

[Henk-Jan van Tuyl]

After activating a default button, another button becomes the default.

When the attached program is run, button 2 is initially the default item: when the enter-key is pressed, an info window appears, saying "Button 2". After closing the info window and pressing the enter-key again, an info window appears, saying "Button 1".
Button 1 has become the default, while button 2 was set as default, using unsafeDefaultItem.

Versions:

Item	Version
OS	Windows XP
GHC	7.6.3
wxWidgets	2.9.5
wxHaskell	0.90.1.0 (currently in Github repository)