position of visibility-option

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36941 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
position of subMenuLeft

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36942 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
always center dialog on screen

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@36943 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e