Deselect a item doesn't work

[SergioGeeK7]

Hello. First of all great work. this table is amazing, but a have an issue

When I try to deselect an item, doesn't work and throw the follow in console

Uncaught TypeError: Cannot read property 'toString' of undefined ->2053 Polymer.html
I have tried two methods: deselectAll and deselect (even at demo page happens this)

Picture: http://i.imgur.com/aWbEdg5.png

But when is multi-selection property active the methods works fine.

[david-err]

Do you happen to have empty strings or explicit null values in your data? If so, please try if #81 solves it.

[SergioGeeK7]

No, is not . even in the demo page happends .. thanks :D

[lousley]

I have the same issue. Are there any news about the solution?

[mtsgrd]

This check fails: https://github.com/David-Mulder/paper-datatable/blob/master/paper-datatable.html#L976

Because here undefined is passed as a parameter instead of null: https://github.com/David-Mulder/paper-datatable/blob/master/paper-datatable.html#L748.

[AlexanderYZhang]

I have this same issue, changing it to null worked for me. Any chance #135 could be accepted? @David-Mulder