It is the purpose
of this note to investigate spaces with regular Gδ-diagonals. Among other
things, it is shown that if X is T1-space, then 1. X admits a development
satisfying the 3-link property if and only if X is a ωΔ-space with a regular
Gδ-diagonal and 2. X is metrizable if and only if X is an M-space with a regular
Gδ-diagonal.