diff --git a/wxPython/src/gtk/_gdi.py b/wxPython/src/gtk/_gdi.py
index bb81158846..3b09aed023 100644
--- a/wxPython/src/gtk/_gdi.py
+++ b/wxPython/src/gtk/_gdi.py
@@ -774,8 +774,8 @@ def BitmapFromBuffer(width, height, dataBuffer, alphaBuffer=None):
     expected to contain a series of RGB bytes and be width*height*3
     bytes long.  A buffer object can optionally be supplied for the
     image's alpha channel data, and it is expected to be width*height
-    bytes long.  On Windows the RGB values are 'premultiplied' by the
-    alpha values.  (The other platforms do the multiplication
+    bytes long.  On Windows and Mac the RGB values are 'premultiplied'
+    by the alpha values.  (The other platforms do the multiplication
     themselves.)
 
     Unlike `wx.ImageFromBuffer` the bitmap created with this function
@@ -804,8 +804,8 @@ def BitmapFromBufferRGBA(width, height, dataBuffer):
     parameter must be a Python object that implements the buffer
     interface, such as a string, array, etc.  The dataBuffer object is
     expected to contain a series of RGBA bytes (red, green, blue and
-    alpha) and be width*height*4 bytes long.  On Windows the RGB
-    values are 'premultiplied' by the alpha values.  (The other
+    alpha) and be width*height*4 bytes long.  On Windows and Mac the
+    RGB values are 'premultiplied' by the alpha values.  (The other
     platforms do the multiplication themselves.)
 
     Unlike `wx.ImageFromBuffer` the bitmap created with this function
diff --git a/wxPython/src/gtk/_gdi_wrap.cpp b/wxPython/src/gtk/_gdi_wrap.cpp
index 6cef0197b2..b5d77798f5 100644
--- a/wxPython/src/gtk/_gdi_wrap.cpp
+++ b/wxPython/src/gtk/_gdi_wrap.cpp
@@ -2925,10 +2925,10 @@ SWIGINTERN bool wxPen___ne__(wxPen *self,wxPen const *other){ return other ? (*s
 #include <wx/rawbmp.h>
 
 
-// See http://tinyurl.com/e5adr for what premultiplying alpha means.  It
-// appears to me that the other platforms are already doing it, so I'll just
-// automatically do it for wxMSW here.
-#ifdef __WXMSW__
+// See http://tinyurl.com/e5adr for what premultiplying alpha means. wxMSW and
+// wxMac want to have the values premultiplied by the alpha value, but the
+// other platforms don't.  These macros help keep the code clean.
+#if defined(__WXMSW__) || (defined(__WXMAC__) && wxMAC_USE_CORE_GRAPHICS)
 #define wxPy_premultiply(p, a)   ((p) * (a) / 0xff)
 #define wxPy_unpremultiply(p, a) ((a) ? ((p) * 0xff / (a)) : (p))    
 #else
diff --git a/wxPython/src/gtk/_misc_wrap.cpp b/wxPython/src/gtk/_misc_wrap.cpp
index cafaf15a44..7308275a5b 100644
--- a/wxPython/src/gtk/_misc_wrap.cpp
+++ b/wxPython/src/gtk/_misc_wrap.cpp
@@ -8175,6 +8175,7 @@ SWIGINTERN PyObject *_wrap_Thread_IsMain(PyObject *SWIGUNUSEDPARM(self), PyObjec
   
   if (!SWIG_Python_UnpackTuple(args,"Thread_IsMain",0,0,0)) SWIG_fail;
   {
+    if (!wxPyCheckForApp()) SWIG_fail;
     PyThreadState* __tstate = wxPyBeginAllowThreads();
     result = (bool)wxThread_IsMain();
     wxPyEndAllowThreads(__tstate);
diff --git a/wxPython/src/mac/_gdi.py b/wxPython/src/mac/_gdi.py
index 51046d2c14..8ea7c71ff2 100644
--- a/wxPython/src/mac/_gdi.py
+++ b/wxPython/src/mac/_gdi.py
@@ -777,8 +777,8 @@ def BitmapFromBuffer(width, height, dataBuffer, alphaBuffer=None):
     expected to contain a series of RGB bytes and be width*height*3
     bytes long.  A buffer object can optionally be supplied for the
     image's alpha channel data, and it is expected to be width*height
-    bytes long.  On Windows the RGB values are 'premultiplied' by the
-    alpha values.  (The other platforms do the multiplication
+    bytes long.  On Windows and Mac the RGB values are 'premultiplied'
+    by the alpha values.  (The other platforms do the multiplication
     themselves.)
 
     Unlike `wx.ImageFromBuffer` the bitmap created with this function
@@ -807,8 +807,8 @@ def BitmapFromBufferRGBA(width, height, dataBuffer):
     parameter must be a Python object that implements the buffer
     interface, such as a string, array, etc.  The dataBuffer object is
     expected to contain a series of RGBA bytes (red, green, blue and
-    alpha) and be width*height*4 bytes long.  On Windows the RGB
-    values are 'premultiplied' by the alpha values.  (The other
+    alpha) and be width*height*4 bytes long.  On Windows and Mac the
+    RGB values are 'premultiplied' by the alpha values.  (The other
     platforms do the multiplication themselves.)
 
     Unlike `wx.ImageFromBuffer` the bitmap created with this function
diff --git a/wxPython/src/mac/_gdi_wrap.cpp b/wxPython/src/mac/_gdi_wrap.cpp
index 631e3a0af5..aae8ef9979 100644
--- a/wxPython/src/mac/_gdi_wrap.cpp
+++ b/wxPython/src/mac/_gdi_wrap.cpp
@@ -2948,10 +2948,10 @@ SWIG_AsVal_short (PyObject * obj, short *val)
 #include <wx/rawbmp.h>
 
 
-// See http://tinyurl.com/e5adr for what premultiplying alpha means.  It
-// appears to me that the other platforms are already doing it, so I'll just
-// automatically do it for wxMSW here.
-#ifdef __WXMSW__
+// See http://tinyurl.com/e5adr for what premultiplying alpha means. wxMSW and
+// wxMac want to have the values premultiplied by the alpha value, but the
+// other platforms don't.  These macros help keep the code clean.
+#if defined(__WXMSW__) || (defined(__WXMAC__) && wxMAC_USE_CORE_GRAPHICS)
 #define wxPy_premultiply(p, a)   ((p) * (a) / 0xff)
 #define wxPy_unpremultiply(p, a) ((a) ? ((p) * 0xff / (a)) : (p))    
 #else
diff --git a/wxPython/src/mac/_misc_wrap.cpp b/wxPython/src/mac/_misc_wrap.cpp
index b9b3258abe..0cd7167ba1 100644
--- a/wxPython/src/mac/_misc_wrap.cpp
+++ b/wxPython/src/mac/_misc_wrap.cpp
@@ -8167,6 +8167,7 @@ SWIGINTERN PyObject *_wrap_Thread_IsMain(PyObject *SWIGUNUSEDPARM(self), PyObjec
   
   if (!SWIG_Python_UnpackTuple(args,"Thread_IsMain",0,0,0)) SWIG_fail;
   {
+    if (!wxPyCheckForApp()) SWIG_fail;
     PyThreadState* __tstate = wxPyBeginAllowThreads();
     result = (bool)wxThread_IsMain();
     wxPyEndAllowThreads(__tstate);
diff --git a/wxPython/src/msw/_gdi.py b/wxPython/src/msw/_gdi.py
index 84c56180f4..f85a8d805c 100644
--- a/wxPython/src/msw/_gdi.py
+++ b/wxPython/src/msw/_gdi.py
@@ -799,8 +799,8 @@ def BitmapFromBuffer(width, height, dataBuffer, alphaBuffer=None):
     expected to contain a series of RGB bytes and be width*height*3
     bytes long.  A buffer object can optionally be supplied for the
     image's alpha channel data, and it is expected to be width*height
-    bytes long.  On Windows the RGB values are 'premultiplied' by the
-    alpha values.  (The other platforms do the multiplication
+    bytes long.  On Windows and Mac the RGB values are 'premultiplied'
+    by the alpha values.  (The other platforms do the multiplication
     themselves.)
 
     Unlike `wx.ImageFromBuffer` the bitmap created with this function
@@ -829,8 +829,8 @@ def BitmapFromBufferRGBA(width, height, dataBuffer):
     parameter must be a Python object that implements the buffer
     interface, such as a string, array, etc.  The dataBuffer object is
     expected to contain a series of RGBA bytes (red, green, blue and
-    alpha) and be width*height*4 bytes long.  On Windows the RGB
-    values are 'premultiplied' by the alpha values.  (The other
+    alpha) and be width*height*4 bytes long.  On Windows and Mac the
+    RGB values are 'premultiplied' by the alpha values.  (The other
     platforms do the multiplication themselves.)
 
     Unlike `wx.ImageFromBuffer` the bitmap created with this function
diff --git a/wxPython/src/msw/_gdi_wrap.cpp b/wxPython/src/msw/_gdi_wrap.cpp
index 0d017c96e3..90edcb85a8 100644
--- a/wxPython/src/msw/_gdi_wrap.cpp
+++ b/wxPython/src/msw/_gdi_wrap.cpp
@@ -2925,10 +2925,10 @@ SWIGINTERN bool wxPen___ne__(wxPen *self,wxPen const *other){ return other ? (*s
 #include <wx/rawbmp.h>
 
 
-// See http://tinyurl.com/e5adr for what premultiplying alpha means.  It
-// appears to me that the other platforms are already doing it, so I'll just
-// automatically do it for wxMSW here.
-#ifdef __WXMSW__
+// See http://tinyurl.com/e5adr for what premultiplying alpha means. wxMSW and
+// wxMac want to have the values premultiplied by the alpha value, but the
+// other platforms don't.  These macros help keep the code clean.
+#if defined(__WXMSW__) || (defined(__WXMAC__) && wxMAC_USE_CORE_GRAPHICS)
 #define wxPy_premultiply(p, a)   ((p) * (a) / 0xff)
 #define wxPy_unpremultiply(p, a) ((a) ? ((p) * 0xff / (a)) : (p))    
 #else
diff --git a/wxPython/src/msw/_misc_wrap.cpp b/wxPython/src/msw/_misc_wrap.cpp
index 67c5935915..3c4279c902 100644
--- a/wxPython/src/msw/_misc_wrap.cpp
+++ b/wxPython/src/msw/_misc_wrap.cpp
@@ -8167,6 +8167,7 @@ SWIGINTERN PyObject *_wrap_Thread_IsMain(PyObject *SWIGUNUSEDPARM(self), PyObjec
   
   if (!SWIG_Python_UnpackTuple(args,"Thread_IsMain",0,0,0)) SWIG_fail;
   {
+    if (!wxPyCheckForApp()) SWIG_fail;
     PyThreadState* __tstate = wxPyBeginAllowThreads();
     result = (bool)wxThread_IsMain();
     wxPyEndAllowThreads(__tstate);