Draw.io: How to get a collapsable container with a header text box (allowing to mix bold/italic)

Relative new to draw.io, but familiar with a lot of other concepts.

I want to have a collapsible container (Advanced-Container) having a header text box so I can have two lines one normal the other bold (when collapsed).

The current collapsible container has a text element which all text share its style, so all bold, or all normal.