When waitMsg is provided in the oprions of form submit, in which there are some field validation errors like allowBlank:false then a Mask appears and hides the entire window and cant able to close it unless we hit browser refresh. (Through the mask the validation red borders for the fields are visible.)
when waitMsg is commented we dont face any problem like that. Previosly(4.0) it was working fine, dont know its due to 4.1 upgrade or not. since before 1 month we have upgraded it and by today only found all the form on validation error has this masking problem.