Here is a roght sample. You set the selections to only repsond to the left mouse button (so that right-clicking does not affect the exisiting selections).
Then in the grid''s mouseup, you can display the menu and act on it. To dot the row, you can set a rowIndex flag, and call grid.RefreshRange so the row is redrawn. In PrepareViewStyleInfo, you can set the borders on this row to be dotted. If you do not like the way this looks, instead of PrepareViewStyleInfo, you can handle CellDrawn, and there if it is a cell in your row being drawn, then decorate the cell in any manner you want. Here is a little sample.
forum12015_9196.zip