SB 3.10 - Strange display in dialog vbox

[KeyPusher]

The red-filled canvas is not displayed correctly in the following example, even though the debug positions and sizes are correct. There should be no space between the gadgets (canvas). The bottom margin is also not maintained.
If all gadget heights are the same and greater than 10, everything is fine.

Code: Select all

 	XML$ = "<window id='0' name='Test' text='Test, what else?' margin='5' minwidth='300' flags='#PB_Window_SystemMenu|#PB_Window_ScreenCentered'>" +
	     "    <vbox margin='0' spacing='5'>" +
	     "      <canvas id='1' height='20' />" +
	     "      <canvas id='2' height='20' />" +
	     "      <canvas id='3' height='5'  /> />" +
	     "    </vbox>" +
	     "</window>"
	
	If ParseXML(0, XML$) And XMLStatus(0) = #PB_XML_Success
		If CreateDialog(0) And OpenXMLDialog(0, 0, "Test")
			Debug "Dialog created"      
		Else  
			Debug "Dialog error: " + DialogError(0)
		EndIf
	Else
		Debug "XML error: " + XMLError(0) + " (Line: " + XMLErrorLine(0) + ")"
	EndIf
	
	Debug ""
	Debug "WindowHeight="+WindowHeight(0)
		
	Width=GadgetWidth(1)
	Height=GadgetHeight(1)
	Debug ""
	Debug "Gadget 1 (blue)"
	Debug "Width="+Width  
	Debug "Height="+Height
	Debug "Y="+GadgetY(1)
	StartDrawing(CanvasOutput(1))
	Box(0,0,Width,Height,$ff0000)
	StopDrawing()
	
	Width=GadgetWidth(2)
	Height=GadgetHeight(2)
	Debug ""
	Debug "Gadget 2 (green)"
	Debug "Width="+Width  
	Debug "Height="+Height
	Debug "Y="+GadgetY(2)
	StartDrawing(CanvasOutput(2))
	Box(0,0,Width,Height,$00ff00)
	StopDrawing()
	
	Width=GadgetWidth(3)
	Height=GadgetHeight(3)
	Debug ""
	Debug "Gadget 3 (red)"
	Debug "Width="+Width  
	Debug "Height="+Height
	Debug "Y="+GadgetY(3)
	StartDrawing(CanvasOutput(3))
	Box(0,0,Width,Height,$0000ff)
	StopDrawing()