Cannot confirm (save) project changes in channel editor

Steps to reproduce:

• log in into cms
• open projects perspective add a project, save and associate channel with project
• go back to project overview and click channel
• in channel editor, make a change
• click confirm button

Expected: project changes are saved into branch

Actual: changes are not saved and a javascript error is logged in js-console of browser:

TypeError: m._confirm is not a function
at t.onClick (channelActions.service.js:76)
at fn (eval at compile (angular.js:15126), <anonymous>:4:263)
at t (angular.js:16213)
at r (angular.js:26592)
at f.$eval (angular.js:17994)
at f.$apply (angular.js:18094)
at HTMLButtonElement.<anonymous> (angular.js:26597)
at HTMLButtonElement.dispatch (jquery.js:5206)
at HTMLButtonElement.g.handle (jquery.js:5014)