diff --git a/lib/mixins/canvas-drawer.js b/lib/mixins/canvas-drawer.js
index 1640776d..cd35a9f8 100644
--- a/lib/mixins/canvas-drawer.js
+++ b/lib/mixins/canvas-drawer.js
@@ -300,7 +300,7 @@ export default class CanvasDrawer extends Mixin {
     for (let i = 0, len = ranges.length; i < len; i++) {
       const range = ranges[i]
 
-      method.call(this, currentRow, range.start - 1, currentRow - firstRow)
+      method.call(this, currentRow, range.start, currentRow - firstRow)
 
       currentRow = range.end
     }
@@ -477,6 +477,7 @@ export default class CanvasDrawer extends Mixin {
     let y = offsetRow * lineHeight
     for (let tokens of this.tokenLinesForScreenRows(firstRow, lastRow)) {
       let x = 0
+      context.clearRect(x, y, canvasWidth, lineHeight)
       for (let token of tokens) {
         if (/^\s+$/.test(token.value)) {
           x += token.value.length * charWidth
@@ -593,6 +594,11 @@ export default class CanvasDrawer extends Mixin {
   drawDecorations (screenRow, decorations, renderData, types) {
     let decorationsToRender = []
 
+    renderData.context.clearRect(
+      0, renderData.yRow,
+      renderData.canvasWidth, renderData.lineHeight
+    )
+
     for (let i in types) {
       decorationsToRender = decorationsToRender.concat(
         decorations[i] != null ? decorations[i][screenRow] || [] : []