Hi,

migration gxt 3.x to gxt 4.0 trial caused me the following error:

Caused by: java.lang.Throwable: (TypeError) : Cannot read property 'indexOf' of null
at Unknown.Ihb(Unknown Source) at Unknown.ulb(Unknown Source) at Unknown.CTd(Unknown Source) at Unknown.wTd(Unknown Source) at Unknown.nKe(Unknown Source) at Unknown.cLe(Unknown Source) at Unknown.nLe(Unknown Source) at Unknown.TKe(Unknown Source) at Unknown.kLe(Unknown Source) at Unknown.BMe(Unknown Source) at Unknown.RNe(Unknown Source) at Unknown.bte(Unknown Source) at Unknown.Wve(Unknown Source) at Unknown.$Je(Unknown Source) at Unknown.k9d(Unknown Source) at Unknown.Qqe(Unknown Source) at Unknown.Tqe(Unknown Source) ... 15 more