[dasher] Fixed Win32 box outline on/off option (#146)

[Patrick Welche <pwelche src gnome org>]

commit 6b49e9d0a19efaa13d054a9839d38bf9e05fe98e
Author: furkandinc <36295973+furkandinc users noreply github com>
Date:   Fri Mar 23 23:27:45 2018 +0200

    Fixed Win32 box outline on/off option (#146)

 Src/Win32/Widgets/Screen.inl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/Src/Win32/Widgets/Screen.inl b/Src/Win32/Widgets/Screen.inl
index 56a9f67f..79cf4a3f 100644
--- a/Src/Win32/Widgets/Screen.inl
+++ b/Src/Win32/Widgets/Screen.inl
@@ -18,7 +18,7 @@ inline void CScreen::DrawRectangle(screenint x1, screenint y1, screenint x2, scr
   if(Colour != -1)
     FillRect(m_hDCBuffer, &Rect, brush);
 
-  if(GetWidth() != (screenint)-1) {
+  if(GetWidth() != (screenint)-1 && iThickness != 0) {
 
     point aPoints[5];