QTreeWidget horizontal scrollbar not working

[Spitfire]

I don't think it's a bug.
It seems to be designed this way.
The scroll bar will apear only when view is reduced below value of headerMinimumSectionSize.
You can set headerStretchLastSection to false and alow user to adjust the width of the column, or set headerMinimumSectionSize to whatever the width of visible items is every time you expand/collapse new item.

QHeaderView is the place to have a look at.

[agqvis]

Thanks, the solution you proposed works.