ngAnimate is throwing the following error when switching the application ui state:
{code}
TypeError: Cannot read property 'classes' of undefined
at resolveElementClasses (/Scripts/lib/angular/angular-animate.js:549:22)
at .../Scripts/lib/angular/angular-animate.js:1188:27
at .../Scripts/lib/angular/angular-animate.js:514:22
at h.$get.h.$digest (.../Scripts/lib/angular/angular.min.js:121:393)
at h.$get.h.$apply (.../Scripts/lib/angular/angular.min.js:123:406)
at HTMLButtonElement. (.../Scripts/lib/angular/angular.min.js:224:239)
at HTMLButtonElement.n.event.dispatch (.../Scripts/lib/jquery/jquery-2.1.1.min.js:3:6404)
at HTMLButtonElement.n.event.add.r.handle (.../Scripts/lib/jquery/jquery-2.1.1.min.js:3:3179) angular.js:11358(anonymous function) angular.js:11358$get angular.js:8445$get.h.$digest angular.js:14017$get.h.$apply angular.js:14227(anonymous function) angular.js:22523n.event.dispatch jquery-2.1.1.min.js:3n.event.add.r.handle
{code}

We are using angularjs version 1.3.0 and ui-router v0.2.11.