Hi,
Currently EA doesn't include support for a Tab control, there is nothing stopping you from typing in "tabcontrol" into the combobox. However the object drawn will only be a standard rectangle. Because a 2 dimensional diagram can only display one tab at a time, in the past I have drawn a number of panels next to each other and added comments to describe the actually way the screen is intended to work.
I way make a note to add support for the stereotype of Tab, however this will not overcome the problem of displaying multiple tabs in a diagram.
Thanks for the feedback.
Paul Mathers