Unfortunately it seems that it's not enough to trigger the scrollbar of the parent.
The solution I found is to set the fixedWidth of the table like this :
int size{ 0 };
for (int i = 0; i < table->columnCount(); ++i)
size += table->columnWidth(i);
table->setFixedWidth(size);
Thanks for the advice mrjj. I used the translate functions and the save and restore to ensure that each section has a logical coordinate system that makes sense to it.
@alogim
Yes, you can, but then you'll need at some point to update the scene's viewport (the QSceneView) manually and this might have some undesirable effects when you move/resize your widget(s).