Avoid events when implicitly selecting first wxBookCtrl page.

The first page added to a wxBookCtrlBase-derived control is always selected,
even if "bSelect" argument of AddPage() was false. This is necessary because
a non-empty book control must always have a selection but the "selection
changed" event generated when doing it is unexpected.

Fix this by not generating any events when the first page is implicitly
selected.

Closes #12075.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65967 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/notebook.cpp

@@ -842,16 +842,7 @@ bool wxNotebook::InsertPage(size_t nPage,
         m_selection++;
     }
 
-    // some page should be selected: either this one or the first one if there
-    // is still no selection
-    int selNew = wxNOT_FOUND;
-    if ( bSelect )
-        selNew = nPage;
-    else if ( m_selection == wxNOT_FOUND )
-        selNew = 0;
-
-    if ( selNew != wxNOT_FOUND )
-        SetSelection(selNew);
+    DoSetSelectionAfterInsertion(nPage, bSelect);
 
     InvalidateBestSize();