Need to display default form for an entity

Hi Team,

I have 3 forms for task activity entity, lets say form1, form2, form 3. When i place an activities subgrid on any form and click plus button, i can add new task. All the forms are getting displayed in the form selector.By default , i need only form1 to be opened up. Please suggest.

Currently if i enter data in form2 and save the form, the next time i open task(from subgrid plus button), i was displayed form2 on create page. I need Form1 here by defauly irrespective of previous history

Thanks
Goutham