Problem:

if you want to place districts the tooltip will often be drawn over the actual location of the mouse cursor, making it invisible.

Repro:
load the game
build a district, which is located on the upper half of the screen
pointing to the district (screenshot 1) will cause the overlay (screenshot 2)

Solutions:

solution A: make the tooltip transparent to a degree.

solution B (preferred): always draw the mouse cursor below, below left or below right of the mouse cursor position.

Savegametooltip.ctr