fixed duplicate field url

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26246 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Reuse old polygons/segments when set()

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26247 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e