From 7ed12d850758d163ab1d2654f13a9cc69a9c8e96 Mon Sep 17 00:00:00 2001
From: Joe Taylor <joe@princeton.edu>
Date: Sat, 10 Sep 2022 09:42:38 -0400
Subject: [PATCH] Suppress the spike seen when horizontal scrolling first
 starts.

---
 widgets/plotter.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/widgets/plotter.cpp b/widgets/plotter.cpp
index 18ab6d4cc..f7fab5934 100644
--- a/widgets/plotter.cpp
+++ b/widgets/plotter.cpp
@@ -334,6 +334,7 @@ void CPlotter::draw(float swide[], bool bScroll, bool bRed)
     int yy=m_h2 - 0.1*m_vpixperdiv*(m_pdB-20.0);
     LineBuf4[m_x].setX(m_x);
     LineBuf4[m_x].setY(yy);
+    if(LineBuf4[m_w-1].y()==0) LineBuf4[m_w-1].setY(yy);
     painter2D.drawPolyline(LineBuf4,m_x);
     if(m_x < m_w-1) m_x++;
   }