From c4165e92b84fd64104dbad366d7706ada7496946 Mon Sep 17 00:00:00 2001
From: kozbial <kozbial@google.com>
Date: Wed, 14 Aug 2019 16:16:48 -0700
Subject: [PATCH] Prevent incorrectly drawing vertical line for zero height
 spacer rows.

---
 .../block_rendering_rewrite/block_render_draw_highlight.js    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js b/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
index 0a9834234..98ccfb5c1 100644
--- a/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
+++ b/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
@@ -151,7 +151,9 @@ Blockly.blockRendering.Highlighter.prototype.drawRightSideRow = function(row) {
   }
   if (this.RTL_) {
     this.steps_.push('H', rightEdge);
-    this.steps_.push('V', row.yPos + row.height - this.highlightOffset_);
+    if (row.height > this.highlightOffset_) {
+      this.steps_.push('V', row.yPos + row.height - this.highlightOffset_);
+    }
   }
 };