Are you reporting a feature or a bug?

Bug

Check if the issue is already reported

http://dev.ckeditor.com/ticket/14630

Provide detailed reproduction steps (if any)

Test tests/plugins/magicline/magicline get size is throwing following exception:

Error details for tests/plugins/magicline/magicline
get size
Values should be equal.
Expected: 9 (number)
Actual:   8 (number)

This is not a regression, it has been that way with earlier versions.

Other details

System specs: win10, window.devicePixelRatio is equals to 2.5 with a 3840x2160 res.

• Browser: Firefox
• OS: Windwos 10