No longer leads to an error in combination with disable-upgrade.

[ghost]

Fixes an issue where an element with this behavior and disable-upgrade throws an error when the element gets detached.

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[ghost]

I signed it!

[googlebot]

CLAs look good, thanks!

[valdrinkoshi]

This is no longer the case with Polymer 2.x or 1.x

[ghost]

Hi,
thanks for your answer but I can recreate the problem in your jsbin for Polymer 1.x.
If the x-key-aware component with disable-upgrade gets removed from the page, detached of the iron-a11y-keys-behavior is called and leads to an error in _unlistenKeyEventListeners.

[valdrinkoshi]

Oh wow, that looks more a Polymer bug rather than of this behavior... Updated the jsbin http://jsbin.com/miqoxuf/3/edit?html,console,output
Mind opening an issue in https://github.com/Polymer/polymer/issues?

[ghost]

Thanks for the updated jsbin! I will open the issue.
Am I right that detached should not be called in this case?