.x-tree-elbow-img {
    &:first-child.x-tree-elbow-empty {
        width: 8px;
    }
}

.x-tree-icon-parent {
    background-image: inline-image('tree/folder-closed.svg');

    .x-grid-tree-node-expanded & {
        background-image: inline-image('tree/folder-open.svg');
    }
}

.x-tree-icon-leaf {
    background-image: inline-image('tree/file.svg');
}

.x-tree-no-lines {
    .x-tree-expander {
        background-image: inline-image('tree/plus.svg');
        background-position: center;
        background-size: 11px;
    }

    .x-grid-tree-node-expanded .x-tree-expander {
        background-image: inline-image('tree/minus.svg');
    }
}
.x-tree-elbow-img {
    &:first-child.x-tree-elbow-empty {
        width: 8px;
    }
}

.x-tree-icon-parent {
    background-image: theme-background-image('tree/folder-closed', 'svg');

    .x-grid-tree-node-expanded & {
        background-image: theme-background-image('tree/folder-open', 'svg');
    }
}

.x-tree-icon-leaf {
    background-image: theme-background-image('tree/file', 'svg');
}

.x-tree-no-lines {
    .x-tree-expander {
        background-image: theme-background-image('tree/plus', 'svg');
        background-position: center;
        background-size: 11px;
    }

    .x-grid-tree-node-expanded .x-tree-expander {
        background-image: theme-background-image('tree/minus', 'svg');
    }
}
Replace inline-image (not supported by Fashion) with theme-background-image
Replace inline-image (not supported by Fashion) with theme-background-image
