>How to enable just one row on grid?

Something like:

if mdown() &&We clicked somewhere
	lnNewRow = 0
	this.GridHitTest(mcol(), mrow(), '', @lnNewRow)
	if lnNewRow <> this.relativerow
		*** We are moving rows!
		nodefault
	else
		*** We are moving columns!
	endif
else
	if inlist(lastkey(), 18, 3, 5, 24)
		*** We are moving rows!
		nodefault
	else
		*** We are moving columns!
	endif
endif

Of course VFP7 makes this easier with RowColChange.