When user clicked Develop:Basic:Highlights (label), it shows "Modify Highlights with +/- Keys".
At this point, can we tell "Highlights" is selected from API?
I tried LrDevelopController.getSelectedTool(), but it seems not for this purpose.
No, there's no way to get or set the Develop slider that's selected in the user interface, unfortunately. Another person recently expressed interest in having that functionality: Lightroom Feature Request - Alternative ways for selecting & activating a develop module slider/control | Photoshop Fami…
Thank you very much for the confirmation and the link.