If a QQuickWidget is inserted into QScrollArea and its width is more than QScrollArea's visible viewport, the contents of this QQuickWidget will paint over any other QQuickWidget 's canvas that "overlaps" the "invisible" part of the original widget.

Test case attached. The "blue" part of the window should only be painted inside qscrollarea's viewport, yet it overlaps to the right if the splitter is high enough so that 2 qquickwidgets canvases intersect.