We present ''CDG Lab'', an integrated environment for development of dependency grammars and treebanks. It uses the Categorial Dependency Grammars (CDG) as a formal model of dependency grammars. CDG are very expressive. They generate unlimited dependency structures, are analyzed in polynomial time and are conservatively extendable by regular type expressions without loss of parsing efficiency. Due to these features, they are well adapted to definition of large scale grammars. CDG Lab supports the analysis of correctness of treebanks developed in parallel with evolving grammars.