Use WS_EX_CONTROLPARENT for wxStaticBox in wxMSW.

This doesn't change anything currently but it seems correct to use this style
with wxStaticBox as it can now contain other windows (and so be "control
parent"), so it could allow Windows or other programs checking for this style
to handle it more correctly.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72662 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/statbox.cpp

@@ -99,11 +99,15 @@ WXDWORD wxStaticBox::MSWGetStyle(long style, WXDWORD *exstyle) const
     if ( exstyle )
     {
 #ifndef __WXWINCE__
+        // We may have children inside this static box, so use this style for
+        // TAB navigation to work if we ever use IsDialogMessage() to implement
+        // it (currently we don't because it's too buggy and implement TAB
+        // navigation ourselves, but this could change in the future).
+        *exstyle |= WS_EX_CONTROLPARENT;
+
         if (wxSystemOptions::IsFalse(wxT("msw.staticbox.optimized-paint")))
-            *exstyle = WS_EX_TRANSPARENT;
-        else
+            *exstyle |= WS_EX_TRANSPARENT;
 #endif
-            *exstyle = 0;
     }
 
     styleWin |= BS_GROUPBOX;