Adding content when menu is collapsed causes it to become unresponsive

[Fitzpasd]

I've uploaded a sample app that displays the issue here.

Changing content and notifying the listeners causes the collapsed menu to move to the top of the screen and become unresponsive.

I've a fix for this issue which I'll submit for PR.

[Fitzpasd]

Initial state of menu. Works as expected.

Press 'add content': Menu moves to top right corner, and no longer responds to input

[matthew-carroll]

I'm not sure if your fix survived the refactor or not. If you see this issue or a similar one recur in 0.9.8, please re-open this issue. Thanks.