"Pin point" feature request

[Morphlng]

Hi! Thank you for developing such an amazing work. Our team is using this to visualize OpenDrive files from Carla Simulator, and creating driving scenarios in OpenScenario format. I'm wondering if it is possible to provide an utility to "pin" a point at specific position, so that we know this location is what we needed.

I'll illustate the functionality more clearly:

1. There might be a "Pin" icon somewhere on the page.
2. The user click this icon, and the mouse turns into a pin.
3. The user click a position on the road/lane, creating a pivot. The mouse may or may not turn back to regular mode.
4. When hanging over the pivot, a pop-up window shows. There are some information that the user can modify, at least naming it and/or leaving notes.

I've tried to implement this with overlay, but resizing causes a lot of trouble. Would you be willing to add this function or can you give me some advice on how to implement it without the source code for this project?