use current mouse position as default position in wxWindow::PopupMenu (works better in wxGTK and is what you need in majority of cases)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@27599 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/mac/carbon/window.cpp

@@ -1439,7 +1439,16 @@ bool wxWindowMac::DoPopupMenu(wxMenu *menu, int x, int y)
 {
     menu->SetInvokingWindow(this);
     menu->UpdateUI();
-    ClientToScreen( &x , &y ) ;
+    
+    if ( x == -1 && y == -1 )
+    {
+        wxPoint mouse = wxGetMousePosition();
+        x = mouse.x; y = mouse.y;
+    }
+    else
+    {
+        ClientToScreen( &x , &y ) ;
+    }
 
     menu->MacBeforeDisplay( true ) ;
     long menuResult = ::PopUpMenuSelect((MenuHandle) menu->GetHMenu() ,y,x, 0) ;