The text in some of my cells is turning blue for no apparent reason. The
cells can't be changed back to black by reformatting or changing the cell
type. It is only hapening to a few cells that don't appear to be different
from other cells in those columns. It seems like it must be some kind of
error, but I can't figure it out. The affected cells have no formulas, have
text as contents and are formatted as General.