Custom popper handles select all text on the page

[Hoogkamer]

Hi, there are 2 issues with the custom popper handles:

• When starting dragging from the handle all text gets selected
• When dragging second time the ghost edge does not appear and cursor shows no-drop icon

notes:

• Tested with Edge and chrome on windows
• It seems to be a recent problem

Reproduce:

• go to first demo link
• choose "use custom popper handles"
• then drag from the handle to a different node to create an edge
  

[maxkfranz]

@Hoogkamer, would you make a PR to address the demo?

The code for custom handles is up to the app, and the demo is just a simple example. There will always be customisations needed, depending on the app itself.

That being said, you're welcome to add a workaround for this particular issue in a PR if you like. It probably just needs a preventDefault().