It's more confusing than useful. We already highlight the common part.
(let ((beg (+ margin (match-beginning 0)))
(end (+ margin (match-end 0))))
(add-text-properties beg end '(face company-tooltip-search)
- line)
- (when (< beg common)
- (add-text-properties beg common
- '(face company-tooltip-common-selection)
- line)))
+ line))
(add-text-properties 0 width '(face company-tooltip-selection
mouse-face company-tooltip-selection)
line)