tdf#116733: Fix expanding in the entries in "Open expert configuration".

The DoubleClickHdl()'s return value does not mean "was handled", but actually
"is there anything more to be done".

Change-Id: Ideeee31db648829546a713148124e3d366941b9a
Reviewed-on: https://gerrit.libreoffice.org/52292Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jan Holesovsky <kendy@collabora.com>
(cherry picked from commit 3af6be55)
Reviewed-on: https://gerrit.libreoffice.org/52304Reviewed-by: Marco Cecchetti <mrcekets@gmail.com>
Tested-by: Marco Cecchetti <mrcekets@gmail.com>

cui/source/options/optaboutconfig.cxx

@@ -570,7 +570,7 @@ IMPL_LINK_NOARG( CuiAboutConfigTabPage, ResetBtnHdl_Impl, Button*, void )
 IMPL_LINK_NOARG( CuiAboutConfigTabPage, DoubleClickHdl_Impl, SvTreeListBox*, bool )
 {
     StandardHdl_Impl(nullptr);
-    return false;
+    return true;
 }
 
 IMPL_LINK_NOARG( CuiAboutConfigTabPage, StandardHdl_Impl, Button*, void )