There is not a simple way to do this, but it can be done without deriving the grid.
In the update Vol 2 refresh release due out this week, there is a new sample in the Formulas samples that does something like this. It is attached. In that sample, if you click on a cell, and start typing a formula like =Sum( and then click on another cell that is at the beginning of the range you want to sum, you can use the arrow + shift keys to extend the range, and it does this without change the current cell where the "=Sum(" is. So, the selected range is being extended without the current cell being changed.
I will forward this request onto the development team so support for extending the range without changing the current cell might be done through a simple property setting instead of the work done in the sample.
CS_e6bf5627.zip
