Collapsed Sidebar CSS

How would it be possible to style the popup label that appears when the sidebar is in the collapsed state?

I.e. in the example

https://snippet.webix.com/y3cz9v7r

how would I get the labels that appear on hover to have the same background as the icons to their left?

Hello,
In such situation, you need to use onMouseMoving event which fires when the mouse was moved over the component, then locate item from event as this.locate(e), get item css by getItem method this.getItem(id).$css
and remove old and set new css as

 var view = popup.getBody().$view;
        webix.html.removeCss(view, this._last_css);
        webix.html.addCss(view, css, true);
        this._last_css = css;

Example: https://snippet.webix.com/q5qetc0w
And onMouseMoving works with every mouse movement, so it’s should to ‘remember’ the last applied class

Great! Thanks for the answer!