I'm still on MM 7.1; so this might have been done already. I threw an error trying to reorder a grid column with a compound field, the following changes avoid the error without changing default MM behavior.

*----------------------------------------------------------
*-- Get the field, cursor name for the ControlSource cursor
*----------------------------------------------------------
*lcField = SUBSTR(tcControlSource, AT(".", tcControlSource) + 1)
*lcCursor = JUSTSTEM(tcControlSource) 

change to:

*----------------------------------------------------------
*-- Get the field, cursor name for the ControlSource cursor
*----------------------------------------------------------
lcField = JUSTEXT(tcControlSource) 
lcCursor = LEFT(tcControlSource, AT(".", tcControlSource) - 1)