Going diagonally towards the image popover closes it

Steps to reproduce:

1. Go to Administer Wiki > Look & Feel > Lightbox and enable it
2. Create a page and add a image to it
3. In view move, hove the image
4. After the popover is displayed go diagonally towards it, to click for example on the `anchor` button

Expected result:
The popover remains displayed and you can click on the anchor.

Actual result:
The popover disappears.
Only when going straight down, using the arrow as 'path', the popover remains displayed. See the screenshot