Expected behaviour

Drag and drop (e.g. dragging component from the add-component-sidebar in the edit mode) works correctly in all supported browsers.

Actual behaviour

1. Dropping doesn't work at all on Firefox - component can't be added.
2. Drag & drop works on Safari, but many items are selected as if preventDefault was missing somewhere.

Live demo with steps to reproduce

https://www.highcharts.com/demo/dashboards/minimal

Product version

Highcharts Dashboards v2.1

Affected browser(s)

Firefox, Safari