Chrome throws "Uncaught TypeError: Cannot read property 'save' of undefined" on every mosaic save

[fredvd]

While debugging another mosaic I notice that the latest relased mosaic 2.1.1 with Plone 5.1 throws a javascript error in the Chrome browser console on every save.

to reproduce, install mosaic, activat mosaic layout on the homepage, edit and select basic layout, press save.

It seems Browser specific as Firefox is not showing the same error. When I enable developer mode and develop javascript on the plone-logged-in bundle it goes into pattern.js, but I have no clue how to debug this further.

VM559 pattern.js:428 Uncaught TypeError: Cannot read property 'save' of undefined
at HTMLFormElement. (VM559 pattern.js:428)
at HTMLFormElement.dispatch (VM543 jquery.min.js:4)
at HTMLFormElement.t.dispatch (VM552 plone-compiled.min.js:1)
at HTMLFormElement.r.handle (VM543 jquery.min.js:4)
at Object.trigger (VM543 jquery.min.js:4)
at HTMLInputElement. (VM543 jquery.min.js:4)
at Function.each (VM543 jquery.min.js:2)
at m.fn.init.each (VM543 jquery.min.js:2)
at m.fn.init.trigger (VM543 jquery.min.js:4)
at m.fn.init.m.fn.(:9090/Plone/front-page/anonymous function) [as click] (http://localhost:9090/Plone/++plone++static/components/jquery/dist/jquery.min.js:5:15442)

Editing of the title/Description field contents works though. Customizing and reordering both tiles and saving also persists.

[djay]

I'm getting a similar error on 5.2 when using mosaic on a collection. Differences are that it says "Changes you have saved may not be saved".
It will still save if you click "leave".

logged-in.js:5 Uncaught TypeError: Cannot read property 'save' of undefined
    at HTMLFormElement.<anonymous> (logged-in.js:5)
    at HTMLFormElement.dispatch (default.js:3)
    at HTMLFormElement.p.dispatch (logged-in.js:3)
    at HTMLFormElement.r.handle (default.js:3)
    at Object.trigger (default.js:3)
    at HTMLInputElement.<anonymous> (default.js:3)
    at Function.each (default.js:2)
    at n.fn.init.each (default.js:2)
    at n.fn.init.trigger (default.js:3)
    at n.fn.init.n.fn.<computed> [as click] (default.js:4)
(anonymous) @ logged-in.js:5
dispatch @ default.js:3
p.dispatch @ logged-in.js:3
r.handle @ default.js:3
trigger @ default.js:3
(anonymous) @ default.js:3
each @ default.js:2
each @ default.js:2
trigger @ default.js:3
n.fn.<computed> @ default.js:4
(anonymous) @ plone-mosaic.js:3
dequeue @ default.js:3
(anonymous) @ default.js:3
each @ default.js:2
each @ default.js:2
queue @ default.js:3
e.mosaic.queue @ plone-mosaic.js:3
exec @ plone-mosaic.js:3
(anonymous) @ plone-mosaic.js:3
each @ default.js:2
each @ default.js:2
e.fn.mosaicExecAction @ plone-mosaic.js:3
(anonymous) @ plone-mosaic.js:2
dispatch @ default.js:3
p.dispatch @ logged-in.js:3
r.handle @ default.js:3