title: why does not submit button work correctly in yii2
body: <p>I am using Kartik tabs to organise my form into multiple forms. For that I divided my form into 3 views where each view represent a tab and contains a part of my form. My problem is that the submitbutton can get the data only from one form and not from all the forms. 
  Can any one give me a simple exemple to help me?</p>
  
  <p>Here I post the kartik tabs link where I have installed it: <a href="http://demos.krajee.com/tabs-x" rel="nofollow">http://demos.krajee.com/tabs-x</a>
  Thank you </p>