use a hidden frame to prevent premature exit on wxMac

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@44588 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

wxPython/wx/tools/helpviewer.py

@@ -26,6 +26,12 @@ import sys, os
 
 #---------------------------------------------------------------------------
 
+def makeOtherFrame(helpctrl):
+    import wx
+    parent = helpctrl.GetFrame()
+    otherFrame = wx.Frame(parent)
+    
+
 def main(args=sys.argv):
     if len(args) < 2:
         print __doc__
@@ -66,6 +72,16 @@ def main(args=sys.argv):
         print "Adding %s..." % helpfile
         helpctrl.AddBook(helpfile, 1)
 
+    # on Mac a menubar and About box are added for HIG compliance, but
+    # the frame used by the HtmlHelpController is set to not prevent
+    # app exit.  So in the case of a standalone helpviewer like this
+    # when the about box is closed that frame will be the only one
+    # left and the app will close unexpectedly.  To work around this
+    # we'll create another frame that is never shown, but which will
+    # be closed when the helpviewer frame is closed.
+    if "wxMac" in wx.PlatformInfo:
+        wx.CallAfter(makeOtherFrame, helpctrl)
+
     # start it up!
     helpctrl.DisplayContents()
     app.MainLoop()