fix hangs on mouse selection in case if wxPython uses wxWidgets with GTK3+ support

This is default configuration on Debian Buster+ and Ubuntu 18.04+.
Probably it'll fix completely problem with 'clipboard already open'
described in the previous commit 5ce6d08f ("make clipboard open minimal time as wxPython documentation recommends")

<?xml version="1.0" encoding="UTF-8"?>
<BeremizRoot URI_location="LOCAL://">
  <TargetType/>
</BeremizRoot>