Fix inappropriate 1-pixel inset inside grouping views (gdiff, 6c01eb2)

Fix alignment bug introduced along with the addition of upper and lower borders. Only the outermost subviews need to be inset by one pixel; additional subviews nested inside the outermost subviews automatically inherit that base positioning and therefore shouldn't specify an additional inset.

Signed-off-by: Greg Hurrell <greg@hurrell.net>