Items in larger layout are not centered

As pointed out in the source req:
"I suspect that because the vertical linear layout is using a grid engine
underneath, the first column is not actually being resized, since its maximum
width is determined by the items inside of it, instead of the size of the
actual layout."

This is exactly what happens. The size of the "column" is only 100 pixels wide, and the widget is aligned inside the column.
With the current API, the column itself cannot be aligned, and its position is therefore at (0,0). This is due to design (the maximum width of a column is always the maximum width of all items inside the column) , but for this case it gives an unexpected result. QGraphicsGridLayout has setColumnMinimumWidth() where the size of the column can be overridden, but QGraphicsLinearLayout does not provide such a function (of obvious reasons)