Sencha Architect render issue on build

I am building an ExtJS application with Sencha Architect.

I want to display a tree grid, but when I export my Application, the grid is displayed completely different. The expand functionality is missing, the icons are missing, even the row height is different than what was displayed inside Sencha Architect. (See Screenshot)

I have encountered similar render issues on different components in the past, but I just ignored them and used a different component.

This is the generated Tree Grid code:

{
xtype: 'tree',
height: '100%',
width: '100%',
store: 'stHitler',
columns: [
    {
        xtype: 'treecolumn',
        width: 159,
        dataIndex: 'text',
        text: 'Text'
    },
    {
        xtype: 'treecolumn',
        width: 150,
        dataIndex: 'balance',
        text: 'MyTreeColumn1'
    }
]
}

EDIT: It seems it's more of a Sencha Architect issue, and not an ExtJs issue.

This happens only when the app theme I'm using has been installed to the application before I use the component that creates the problem, so it probably hasn't included the specific component when the scss is built (?).

If I replace the theme in the application with a new one, the problem is solved, at least until I add again a new component that did not exist when I installed the theme.

What is the solution to this problem? It is not possible each time I add a new component to add a new theme and customize it from the beginning all over again. Also rebuilding the SCSS doesn't seem to fix the problem.