How to make blocks of text in different colors in Motion

Trying to figure out the Motion feature in Fresco.  I've mostly got illustrations figured out, but I'm trying to have blocks of text appear sequentially in different colors.  Example: Frame One - "The" in black.  Frame Two - add "Quick" in green, so "The Quick" appears in two colors.  Frame Three - "Brown" in brown, so that "The Quick Brown" appears in three colors, etc., etc.  But when I try to do this, Frame Two's text wipes out/replaces Frame One's(?!).  Is it possible to copy/paste text into Motion frames from non-motion frames?  Help!