That’s because, from DxO’s PLv7 design perspective, (since the demise of the big "Local Adjustments button), there is no longer the concept of 2 modes … Global & Local.
Like you, however, I find this often confusing and really annoying !!
There’s more, and broader, discussion on various issues related to PLv7’s new approach to Local Adjustments here … with links to requests & suggestions that you can vote for.