A fresh stash contains a single default tab with the name “Stash Tab 1”. It seems that this is always the first tab opened when opening the stash no matter what name is given to the tab or where the tab is placed amongst other tabs i.e. in another category or at the end of the list. It is always the tab selected.
This is a bit annoying organizationally as I like to create a dump tab, fill it up, and recategorize it to a dump category. This described behavior means I always need at least one extra click when dumping to get to my current dump tab.