Hi Matthias,
I think the following procedure works to keep the original contour formatting:
1) After adding the rows/cols, make a dummy contour from the enlarged worksheet range
(to create an enlarged virtual matrix)
2) Open Plot Setup for the contour plot in the original contour profile, (You see the second
virtual matrix in the top panel.)
3) Select the new virtual matrix in the top panel. Make sure the original virtual matrix has
already selected under Layer1. Turn on the check box of the Z dataset in the middle panel.
4) Press "Replace" button. (You see now the new virtual matrix has replaced the original
in the bottom panel.) Click OK.
5) Press the Rescale button (or "Graph: Rescale to Show All" menu) for the layer1.
Hope this helps.
--Hideo Fujii
OriginLab