New user simple question

When you add a new component to your app for the first time, you will need to run an app build. Sencha Cmd only includes the CSS styles (built via SASS) only for the components your app is using.

So if you added Ext.grid.Panel for the first time to your app, your app doesn't have the styles and the "sencha app build" or "sencha app build testing" will regenerate the CSS and include the Ext.grid.Panel styles if that class was properly required.

New user simple question