Extjs 4 Loading a view from controller 2

Continui开发者_开发技巧ng the question here: Extjs 4 MVC loading a view from controller how do you load the created view into your viewport?

Here is what I did:

this.getViewportContent().insert(Ext.widget('templatecategorycreate'));

where getViewportContent() returns where I wanted to add that view to, but it does not work. Error was:

Uncaught TypeError: Cannot call method 'substring' of undefined

And the answer is as simple as:

this.getViewportContent().add(Ext.widget('templatecategorycreate'));

Can't believe I had to debug the whole extjs trace to get into this...