[john.gersh]

If by "it stays within the confines of the text box its associated with" you meant that the tab removal affects only that one instance of textbox or shape and not subsequently-created ones, I'm afraid that seems to be the case. There doesn't seem to be a way to specify default tab settings for new textboxes or shapes. They're not saved as part of a style, either.

On the other hand, tab settings are carried over when you duplicate or copy-paste a shape. This means that you can create a stencil of textboxes and common shapes with particular tab settings and use those when you need them.