diff --git a/package.json b/package.json
index 98a03e5..c226784 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "easy-marker",
-  "version": "1.1.23",
+  "version": "1.1.24",
   "description": "Easy marker",
   "main": "dist/easy-marker.esm.js",
   "scripts": {
diff --git a/src/base_easy_marker.js b/src/base_easy_marker.js
index 384f0c7..9fcd195 100644
--- a/src/base_easy_marker.js
+++ b/src/base_easy_marker.js
@@ -589,7 +589,7 @@ class EasyMarker {
     if (this.options.adjustTextStyleDisabled) return
     const { children } = this.container
     for (let i = 0; i < children.length; i++) {
-      children[i].style.zIndex = '40'
+      children[i].style.zIndex = '10'; // @fix 40 -> 10。理论上要比HighlightLine和Cursor等元素要低的吧
       children[i].style.position = 'relative'
     }
   }
diff --git a/src/element/highlight.js b/src/element/highlight.js
index 021d6fc..8889cef 100644
--- a/src/element/highlight.js
+++ b/src/element/highlight.js
@@ -244,11 +244,13 @@ export default class Highlight extends BaseElement {
   }
 
   createLine(pointList) {
+    const line = document.createElementNS('http://www.w3.org/2000/svg', 'line')
+    if (!pointList[2] || !pointList[3]) return line;
+
     const x1 = pointList[2][0]
     const y1 = pointList[2][1] + 1
     const x2 = pointList[3][0]
     const y2 = pointList[3][1] + 1
-    const line = document.createElementNS('http://www.w3.org/2000/svg', 'line')
     line.style.stroke = this.option.underlineColor
     line.style.strokeWidth = this.option.underlineWidth
     line.setAttribute('x1', x1)