PyQt(Qt): unexpected scrollbars in QCanvasView

[Konrad Koller]

For a card playing game I constructed a layout of 49 playing cards
(size of each: x=71, y=96) which are arranged in a 7X7 matrix side by
side. Accordingly the pysical size of the Canvas is x=71*7, y=96*7:

in the main program:
canvas=QCanvas(497,672)

class Board(QCanvasView):
	def __init__(self,canvas,parent):
		QCanvasView.__init__(self,canvas,parent)

but QCanvasView produces a layout with scrollbars in both directions.
This is very annoying for the player because although the screen's
size is more than appropriate for a total layout only some of the
cards can be viewed without scrolling. The QScrollView documentation
states that as default QScrollView shows a scrollbar when the content
is too tall to fit and not else. What goes wrong?
I am using PyQt 3.11 and Qt 3.3.1 under Linux.
Thanks for any help.