title: Q: DevExpress TreeListLookUpEdit
body: <p><img src="https://i.stack.imgur.com/23klB.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/LCd3m.png" alt="enter image description here"></p>
  
  <p>i want to add the button like plus beside the dropdown button like the picture</p>
  
  <p>I don't have a problem writing the problematic code. I want to add a button in the outline design of the TreeListLookUpEdi. When I click on this button, which resembles the plus icon in the image, I add code.
  Like opening a new window and adding new items to TreeListLookUpEdit</p>