Disabled TabPanel - First form shown still Enabled?

As noted in the title - when I disable a tabPanel in the onLoad event the first form shown in the panel is still enabled and editable?

The Tabs are disabled but not the first form. Is this expected behavior? I had anticipated that if a tabPanel is disabled then all of its contents should be disabled too??

Obviously I can disable the first form too but seems like something that should be part of the tabPanel display logic.

Ian