Please see this answer from macuser.
If the 1099-DIV has a box 7 foreign tax then you should enter the portion of box 1 that generated the foreign tax. Often that will be the box 1 amount if all the foreign tax came from the same source but in the case of some mutual funds only a portion of box 1 will be what generated the foreign tax. Most brokers list the foreign tax and the source of that tax somewhere in the composite statements that they send.
