xfce4-screenshooter -r -d X does not delay the capture for X seconds. The screen is immediately grayed out for selecting the capture area and the capture is done at the completion of the region selection. -d works when used with either -f or -w Verion 4.12 of XFCE Version 1.8.2 of xfce4-screenshooter I'm fairly new to XFCE and have no experience with other versions.
Created attachment 6544 makes delay applicable for region mode Yeah this bugged me, too.
Hand-applied with minor edits in the commit messages in 24cc58d, 6cacb54 and 38f1d09