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/common/bookctrl.cpp

@@ -471,6 +471,19 @@ int wxBookCtrlBase::GetNextPage(bool forward) const
     return nPage;
 }
 
+bool wxBookCtrlBase::DoSetSelectionAfterInsertion(size_t n, bool bSelect)
+{
+    if ( bSelect )
+        SetSelection(n);
+    else if ( m_selection == wxNOT_FOUND )
+        ChangeSelection(0);
+    else // We're not going to select this page.
+        return false;
+
+    // Return true to indicate that we selected this page.
+    return true;
+}
+
 int wxBookCtrlBase::DoSetSelection(size_t n, int flags)
 {
     wxCHECK_MSG( n < GetPageCount(), wxNOT_FOUND,