Element picker tools don't work

[ghost]

Filter issues MUST NOT be reported here. Read first: https://github.com/gorhill/uBlock/blob/master/CONTRIBUTING.md

Describe the issue

The element picker tools do not work. If I click on them nothing happens.

One or more specific URLs where the issue occurs

[URL(s) for issue on a specific site are mandatory]

Screenshot in which the issue can be seen

[Screenshot(s) for visual issues are mandatory]

Steps for anyone to reproduce the issue

1. OPen Safari and browse to a random page
2. Use the element picker tools - nothing happens
3. This issue does not occur in Chrome with the same version of uBlock origin

   Your settings

[If you fail to provide this info, I will mark the issue as invalid. Lists all settings which differs from default settings]

• MacOS version: 10.13.3
• Safari version: 11.0.3
• uBlock Origin version: 1.14.24

Your filter lists

[Example: "Default filter lists + FRA", or "Default filter lists minus uBlock -- Badware risks"]

Your custom filters (if any)

[gorhill]

Duplicate of #88.