Totally independant forms in tabcontrol

Totally independant forms in tabcontrol

I'm designing an application on VB.net and I'm newbie as well. I thought
about the general architecture of the application and came up with the
following idea.
the application is made of different modules
the user can run different modules in the same time
each module will run his main form in a different tab in tabcontrol
each module has his own modal forms, modeless windows, messages, ... etc.
Before going through much development details, I started first with trying
this design. Though, I couldn't first embed dynamically a form in tab
during run time and even after some workarounds, I couldn't make the
modules run perfectly in parallel. For example when I have a modal window
displayed in a module, the whole application freezes while I expect only
the related tab to freeze and be able to switch to the others to do some
work.
Does anyone know how to make the tab contents completely separate and not
have one freezes the other ?
Thank you.