Since the version 1.5, changes on a shared layer are visible in navigator or in pages listings on all pages which share it.

In versions prior to 1.5

Changes on a shared layer may not be visible in navigator or in pages listings on all pages which share it.

This is due to the fact that listings displays a bitmap, which get refreshed by Fred4 on page save. In case of a layer, shared with more pages, only the bitmap of the page saved in Fred4 gets refreshed.

In other words, if a layer of the page 8 in the first edition is shared with the page 5 in the second edition, when you save the page 8 in Fred4, the bitmap of the page 5 in the second edition is not refreshed.