L.EditToolbar._checkDisabled is setting the leaflet-disabled class incorrectly

[markgibbons25]

Toggling this class won't work because if you add or remove layers from the feature group it will just toggle the class on or off without taking into account whether the featuregroup actually has any layers.

[jacobtoye]

Ah nice find, I calculate hasLayers but don't use it for toggling :| Will fix.

[joeybaker]

This is kinda a big deal for us – any chance a quick update can be issued?

[jacobtoye]

Thanks @joeybaker, I don't know what I was think writing that code :\