It would be nice if a multiselection would allow you to select a find and replace function (the same, which is in use in word) to be able to change cell contents quickly.
It seems, you are considering the iGrid control as a black box that should provide you with all major functions of electronic worksheets app. iGrid is more a lightweight and compact grid control similar to MS ListView or FlexGrid, and it does not have a rich user interface with functions like this. It is implied that you can add features like the requested one yourself based on the basic cell matrix functionality.

But it's nice you made your suggestion public here. If a lot of other developers vote for incorporating this into iGrid, we will consider this idea.