One way you could do this would be to change your calculation to be similar to the following:
if [Company Id] = [Select a company] then "Selected" else " " end
Then, place it on the Label shelf.
Hope this helps!
Attached is an example of the type of calc Tracy is describing. I typically use a 1 or 0 to keep it as simple as possible (and while in this case it probably makes very little difference to performance, integer or n calcs will always be faster than String calcs).
Thanks for your answers but I think I have explained it bad.
I would like something like this:
The colors of the companies must be kept, and when I select a company "a mark" (it could be a line or whatever makes a difference among the rest) must be shown.
Thanks and sorry for the misunderstanding.
Sorry, perhaps Tracy was suggesting something different in that case.
Here's a workbook that places an X in the selected value's area.
Notice I'm using the "Square" mark type. I believe you could use "Bar" as well, but don't change the mark type to "Text" or you'll only color the text inside the cell, which in this case, would only be the selected value of 3.
Thank you very much!