I have a grid that allows the user to selects rows when clicking on any cell of the row.

The grid is set to allow multi-selection.

When the user click with the Left Mouse it will select the row.  An anchor point of you will.

When they Shift + Left Mouse click, it will extend the selection from the last Left Mouse click row to the current Shift + Left Mouse click row.

This is all provided by the grid "as is".  Thanks Infragistics!

I need to do the exact same thing with the Middle Mouse click acting as the anchor point.  I have intercepted the Middle click and have Selected & Activated the row under it.  The problem comes down to when I want to extend from where the Middle Mouse click was last clicked (anchor point) to where the Shift + Left Mouse click is occurring, it will extend the last Left Mouse click and not the last Middle Mouse click.  I was assuming it would extend from the Active row which obviously it does not.

I assume that this has to do with the Selection Strategy but am not seeing anything I can tweak to make my Middle Mouse clicked row behave like the Left Mouse click row.

Any ideas?

What am I really doing you might ask?  A Left Mouse click on a row will load something in the "current" window.  A Middle Mouse click will load it in a "new" window.  Extending selections of rows allows other "things" to occur.