You can try doing it manually:
- main widget:
- the panel:
- panel entry:
- in the panel widget:
We collapse the text pieces with a mouse click:
You could isolate which mouse button does what. This is the default behaviour where LMB is consumed by the button and does not extend the panel, any other mouse button would.
Since each entry is a separate widget, you could easily achieve this highlight effect across the line:
