Leaflet: Hover on L.SVG paths after map pan is broken on firefox

I can reproduce by panning the map once (in any direction), so that features don’t overlap with their old positions. Firefox 57.0.4 (64-Bit) and Firefox Nightly 59.0a1 (2018-01-19) (64-Bit) on Ubuntu 16.04.

Interactive Leaflet demo

From using the Firefox Inspector to see what changes when panning the map, I created the following demos that reproduce the issue without Leaflet:

Interactive demo without Leaflet

Automated test

The observed change when panning the map is moving (transitioning) the leaflet-map-pane and the svg elements. Simplified example as in the demo:

    pane.style.transform = 'translate3d(200px, 0px, 0px)';
    svg.style.transform = 'translate3d(-200px, 0px, 0px)';
    svg.setAttribute('viewBox', '-200 0 400 200');

The corresponding Leaflet code parts are:

https://github.com/Leaflet/Leaflet/blob/ae8a1a645a3ed2c2637b6ae9056f0c1ff794949c/src/map/Map.js#L1219-L1221

https://github.com/Leaflet/Leaflet/blob/ae8a1a645a3ed2c2637b6ae9056f0c1ff794949c/src/layer/vector/SVG.js#L97-L99

I don’t know what is the problem. I don’t know how I can reproduce the problem on my computer. I do not know if the problem happens on all web browsers.

I do not know if the problem happens when panning the map with the mouse, or with a touchscreen, or with the keyboard, or with all. I don’t know if the problem happens when doing one thing at once, or several things at once.

We do not have enough information to know what the problem is.

This is now fixed in current Firefox 65.

Mhhh… they might be related but not exactly “our” problem (both seems to be precision-related, this one seems not)… so I guess I’ll file a new one: Bugzilla 1486952

No, I haven’t yet. Go for it.

I had a hard time searching Bugzilla for already existing bugs, closest I could find by searching the SVG Component page, but not sure if related:

• 1424758 - SVG rendering of transformed group members leads to eventable area being offset from visual rendering of elements
• 1416178 - Inaccurate mouseover regions for elements with coordinates in unit interval when SVG child of transformed DIV

I confirm. Firefox 55.0.2 (64-bit) for Linux Mint.

My English is poor! But the problem I say is really exists!