[plt-scheme] grid or spreadsheet GUI widget

Hi,

I will need a grid or spreadsheet style GUI widget in my 
application. I have some ideas and some preliminary work.
However I would like to ask two questions:
- Is it possible to position some sort of an editor% or text%
  in a canvas%? I am thinking of pixel positioning. I thought
  I would need this to easily edit a cell and I could avoid
  implementing an edit box.
- Is it possible to create this GUI widget with some snips?
  If yes, can someone point me to a similar usage of snips?
  Somehow I still do not fully understand the use of snips. :-(

Thanks,

Peter Ivanyi