To reproduce:
1) Create a new project
2) Select something that would have a slider in Inspector (for example, Camera object in the hierarchy)
3) Hold mouse button on the slider and scroll left and right to change its value

Expected: Cursor can wrap around the screen and scroll infinitely in either direction
Actual: It stops at an edge and can't move further in that direction

Reproduced in 2017.4.0f1, 2019.1.1f1, 2019.3.0a3