Thanks for your reply.
In your instruction 2: there is no form. I'm just designing a subclass. What should I click on? There is no form so I can't click on the title bar of the form.

Thanks!

1. In Properties Window select the column.
2. Click on Title bar of the form.
3. Click on the control you want to add in Toolbar, Just click no drag & drop.
4. Click in the column.