Make sure app works after return from Open Screen

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@32978 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Less debugging

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@32979 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
#4207 Add the tab panel

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@32980 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e