Sencha Build Error When Viewed In Browser

I have finally managed to create a production build of my sencha web app using Cmd 3.10.2.342 and touch 2.2.1 All my bespoke files are included and deltas are created as one would

Solution 1:

I traced this back to issues/conflicts with itemId and id where sencha was telling me that a component already existed and should be destroyed.

Solved it by removing id and itemId and used cls instead