[cas] fix Flatten[{2, 3, {5, 1}, {{2, 1, {3}}}}]

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@38114 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Exam mode: confirmation dialog customized

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@38115 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e