Certain conditions relating to window size VS tooltip placement, result in a duplicate tooltip being shown in 2 positions

[iaremarkus]

It seems that there's an overlap in placement logic, that results in a tooltip being shown twice, in 2 positions.

See the gif below that highlights what happens when you scroll and the tooltip becomes confused if top or right is the better placement, so it just does both :P

Perhaps related to 521

[boly38]

duplicate tooltip related another issue: #645