Button by default disabled on EditorDescriptorAttribute

Hi,

I'm using EditorDescriptorAttribute for IList 

[Display(Name = "Answers", GroupName = PropertyGroupNames.Question, Order = 80)]
[EditorDescriptor(EditorDescriptorType = typeof(AnswerListPropertyDescriptor))]
[Required]
[ListItems(2,10000)]
[PropertyListCheckbox]
public virtual IList<QuestionnaireAnswerBlock> Answers { get; set; }

It opens as a custom editor with a textbox and checkbox with two buttons for Submit and Cancel

Submit button is bydefault disabled and enables only when a checkbox is checked/unchecked in editor.

I want it to be enabled by default.

How to do this? Please help.