Hi Zentara, not quite sure what the post you linked to has to do with my problem. curselection gives indices of the cells not of strings inside the cells. And I want to modify the formatting of a section of the content of a given cell (for which I would need some indices to indicate which part of the content should my formatting apply to).
Sorry I didn't understand the question. From what I little I know, the only thing you can do with a TableMatrix is use the -selectcommand to pop a toplevel window with the cell's data into a text widget for editing. Maybe a smarter monk might know a way.