When the mouse hover a cell it displays the cell contents i

When the mouse hover a cell it displays the cell
contents in a context box. How can I control this text and have my own text
instead of what is already in the cell? I might want to put an acronym in the
list cell but display the full text when the mouse hover over the top of that
cell?

Existing excells always show
exact value of a cell. Basically exCell can show different values ( each exCell
has a getTitle method which used for hovering) but so far no one from existing
excell provide such functionality