The view doesn't have any associated frame when using the special "single
view" mode in the sample, so don't try to show it when creating a new view.
This resulted in a crash when starting the sample with --single command line
parameter.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@68024 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775