Disabled items are erroneously allowed to be dragged

[kartik-v]

I'm opening this issue because:

• disabled items should never be draggable and sortable

supporting information:

• I use sortable version: latest version
• I tested in the following browser (incl. versions): Chrome
• Windows, OS X/macOS, or Linux?: Windows

How can the issue be reproduce the problem?

Steps to reproduce:

• Navigate to the examples page
• Go to the third example of Exclude Items
• The positive test works - Try dragging the normal enabled list items a few times
• The negative test fails - Try dragging the disabled item - you can drag it by hard holding the mouse on the item and slightly dragging it left or right - then you can place it anywhere before or after other items
• When you try to drag the disabled item - it allows you to thus drag and move / reorder the item - which as per definition should not be draggable

Thank you for contributing!

• Please make sure your contribution is in line with the contribution guidelines:
  https://github.com/lukasoppermann/html5sortable/blob/master/CONTRIBUTING.md

• Participation in this open source project is subject to the Code of Conduct:
  https://github.com/lukasoppermann/html5sortable/blob/master/CODE_OF_CONDUCT.md

Before creating a feature requests, please review the existing feature requests and make sure there isn't one that already describes the feature you are missing:
https://github.com/lukasoppermann/html5sortable/issues?q=is%3Aopen+is%3Aissue+label%3Afeature

What's the feature?

What problem is the feature intended to solve?

Is this feature similar to an existing feature in another project?

[lukasoppermann]

Hey, thanks for the report. It is very hard to reproduce in chrome, but once I got it too.

It would be really awesome if you could send a PR with a fix.