Hello @blankon, you can already run BSP2 in a new tab. Simply click on the magnifier glass button in the search box, and click "Open BSP2 in a tab" in the menu. Hope this meets your need :-)

For integration with "Tree Style Tab" add-on, this would require the developer of that add-on to allow other add-ons to open sub-windows inside it, which is not the case today (to my knowledge). Maybe in future if he/she adds that integration feature ?

Thank you, aaFn.

=================== Edit ===============
In 2.0.73, I added the function to "Open BSP2 in a tab" on the right click menu of the BSP2 icon in the toolbar.
This allows you to keep "Tree Style Tab" in your sidebar, and to activate the feature without switching TST first.

This should answer your need, cheers aaFn.