1. Tooltips only show up on point and click
When the tab bar scrolls and your cursor is stationary while tabs scroll by underneath, the tooltips don't show up to prevent flashing of tooltips. Tooltips will only show up when explicitly pointing with the cursor.
2. Mobile interactions
Clicking once does the same thing as hovering on desktop so that you can preview the big number before deciding if you want to see all. It maintains the ability to see the isolated views one tap away without needing to use the visual indicator of "View all" text repeated down every single legend item.
3. Hover interactions on segments
The large % number stays the same width so that the smaller text doesn't do slight jumps around while hovering, making it easier to read. Upon hovering over items, "View employees" appears for affordance that clicking does something, and other items are greyed out to give the hovered segment emphasis.
4. Hover interactions on employee pills
When filling in the employee list of folks to nudge, the list can get long given larger employers are mostly using this feature. If you're adding somebody and not sure if you already added them, hovering over a person that's already been added will turn their pill black in the text input for easy identification.