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kotlinlang

I think this summarizes the behavior...It looks like the tools have the concept of a Group.  In the case of your single 3 item group, the other tools are displaying them exclusively or as part of a secondary tabbing structure.

For example, in IntelliJ, I have Favorites, EJB, and Web in the lower-left and Project and Structure in the upper-left.  I either show Project or Structure so the ordering isn't relevant.

VisualStudio, EA, and Dreamweaver let you combine items in this thing I'm calling a Group so that they themselves are tabbed.  This makes the ordering irrelevant because the particular tab is either showing or it's not showing.