How to reproduce

• Leaflet version I'm using: 1.1.0
• Browser (with version) I'm using: Chrome Version 59.0.3071.109
• OS/Platform (with version) I'm using: Mac OS X 10.11.6

I came across this problem when using a modified version the Rrose Plugin.
I reduced the code as much as possible for a reproduction example:
http://playground-leaflet.rhcloud.com/bijew/edit?html,console,output

The part of the code that causes the Problem is this:

L.DomEvent
    .disableClickPropagation(wrapper)
    .disableScrollPropagation(this._contentNode)
    .on(wrapper, 'contextmenu', L.DomEvent.stopPropagation);

Changing it to

L.DomEvent
    .disableClickPropagation(wrapper)
    .disableScrollPropagation(this._contentNode);
L.DomEvent.on(wrapper, 'contextmenu', L.DomEvent.stopPropagation);

fixes the Problem.

Prior to 1.1.0 this worked and the Documentation states that disableScrollPropagation should return this (which should be L.DomEvent).