Highlight cells that are referenced from the selected mapping expression
This is a nice to have (maybe in version 2.0): When the user selects a mapping expression, it would be nice to highlight in the spreadsheet preview the cells that are referenced in that expression. In case of references that contain the '*' character to refer to range of cells and/or column, the start/end row/column parameters should be used to calculate the appropriate range of cells within the spreadsheet. It would be nice if similarly to MS Excel, different references could be highlighted with different background colors.
This would be sweet. To go further, one could imagine selecting individual highlighted cells and previewing the text rendering of the associated MM expression using the value from that cell.
Related to #27