AltSnap 1.63
in the [Zones] section
ShowZonesPrevw=1
; Enable/Disables Layout preview (default 1)
ZonesPrevwOpacity=160
; Opacity from 0-255 of the Zone preview (default 160).
; Use 0 if you disabled Desktop composition.
ZonesPrevwBGCol=FF FF FF
ZonesPrevwBDCol=00 00 00
; Color of the Snap Layout preview, ZonesPrevwBGCol for background color
; and ZonesPrevwBDCol for the border color. default are white and black.
; Use a dark beckground and a light border if you use dark theme.