diff --git a/redo/container.go b/redo/container.go
index f323952..c855072 100644
--- a/redo/container.go
+++ b/redo/container.go
@@ -12,10 +12,11 @@ type allocation struct {
 }
 
 type sizingbase struct {
-	xmargin		int
-	ymargin		int
-	xpadding		int
-	ypadding		int
+	xmargin			int
+	ymargintop		int
+	ymarginbottom	int
+	xpadding			int
+	ypadding			int
 }
 
 type controlSizing interface {
@@ -41,7 +42,8 @@ func (c *container) resize(x, y, width, height int) {
 		return
 	}
 	d := c.beginResize()
-	allocations := c.child.allocate(x + d.xmargin, y + d.ymargin, width - (2 * d.xmargin), height - (2 * d.ymargin), d)
+	allocations := c.child.allocate(x + d.xmargin, y + d.ymargintop,
+		width - (2 * d.xmargin), height - d.ymargintop - d.ymarginbottom, d)
 	c.translateAllocationCoords(allocations, width, height)
 	// move in reverse so as to approximate right->left order so neighbors make sense
 	for i := len(allocations) - 1; i >= 0; i-- {
diff --git a/redo/container_darwin.go b/redo/container_darwin.go
index 4936a62..8b98b64 100644
--- a/redo/container_darwin.go
+++ b/redo/container_darwin.go
@@ -51,7 +51,8 @@ func (c *container) beginResize() (d *sizing) {
 	d = new(sizing)
 	if spaced {
 		d.xmargin = macXMargin
-		d.ymargin = macYMargin
+		d.ymargintop = macYMargin
+		d.ymarginbottom = d.ymargintop
 		d.xpadding = macXPadding
 		d.ypadding = macYPadding
 	}
diff --git a/redo/container_unix.go b/redo/container_unix.go
index 4beccef..fbfd993 100644
--- a/redo/container_unix.go
+++ b/redo/container_unix.go
@@ -58,7 +58,8 @@ func (c *container) beginResize() (d *sizing) {
 	d = new(sizing)
 	if spaced {
 		d.xmargin = gtkXMargin
-		d.ymargin = gtkYMargin
+		d.ymargintop = gtkYMargin
+		d.ymarginbottom = d.ymargintop
 		d.xpadding = gtkXPadding
 		d.ypadding = gtkYPadding
 	}
diff --git a/redo/container_windows.go b/redo/container_windows.go
index e1470cc..d3fd327 100644
--- a/redo/container_windows.go
+++ b/redo/container_windows.go
@@ -107,7 +107,6 @@ const (
 	paddingDialogUnits = 4
 
 	groupXMargin = 6
-	// TODO
 	groupYMarginTop = 11		// note this value /includes the groupbox label/
 	groupYMarginBottom = 7
 )
@@ -125,7 +124,8 @@ func (c *container) beginResize() (d *sizing) {
 
 	if spaced {
 		d.xmargin = fromdlgunitsX(marginDialogUnits, d)
-		d.ymargin = fromdlgunitsY(marginDialogUnits, d)
+		d.ymargintop = fromdlgunitsY(marginDialogUnits, d)
+		d.ymarginbottom = d.ymargintop
 		d.xpadding = fromdlgunitsX(paddingDialogUnits, d)
 		d.ypadding = fromdlgunitsY(paddingDialogUnits, d)
 	}
@@ -134,7 +134,9 @@ func (c *container) beginResize() (d *sizing) {
 		// this is because Windows groupboxes have the client rect spanning the entire size of the control, not just the active work area
 		// the measurements Microsoft give us are for spaced margining; let's just use them
 		d.xmargin = fromdlgunitsX(groupXMargin, d)
-		d.ymargin = fromdlgunitsY(groupYMarginTop, d)
+		d.ymargintop = fromdlgunitsY(groupYMarginTop, d)
+		d.ymarginbottom = fromdlgunitsY(groupYMarginBottom, d)
+
 	}
 
 	return d