Fix equals function on TextSourceRange when imposter elements are used

2 files changed, 20 insertions, 4 deletions

diff --git a/ext/fg/js/document.js b/ext/fg/js/document.js
index db9f0cdc..71654b29 100644
--- a/ext/fg/js/document.js
+++ b/ext/fg/js/document.js
@@ -110,6 +110,7 @@ function docRangeFromPoint(x, y, deepDomScan) {
     const elements = docElementsFromPoint(x, y, deepDomScan);
     let imposter = null;
     let imposterContainer = null;
+    let imposterSourceElement = null;
     if (elements.length > 0) {
         const element = elements[0];
         switch (element.nodeName.toUpperCase()) {
@@ -117,9 +118,11 @@ function docRangeFromPoint(x, y, deepDomScan) {
             case 'BUTTON':
                 return new TextSourceElement(element);
             case 'INPUT':
+                imposterSourceElement = element;
                 [imposter, imposterContainer] = docImposterCreate(element, false);
                 break;
             case 'TEXTAREA':
+                imposterSourceElement = element;
                 [imposter, imposterContainer] = docImposterCreate(element, true);
                 break;
         }
@@ -131,7 +134,7 @@ function docRangeFromPoint(x, y, deepDomScan) {
             docSetImposterStyle(imposterContainer.style, 'z-index', '-2147483646');
             docSetImposterStyle(imposter.style, 'pointer-events', 'none');
         }
-        return new TextSourceRange(range, '', imposterContainer);
+        return new TextSourceRange(range, '', imposterContainer, imposterSourceElement);
     } else {
         if (imposterContainer !== null) {
             imposterContainer.parentNode.removeChild(imposterContainer);
diff --git a/ext/fg/js/source.js b/ext/fg/js/source.js
index 5cdf47b5..11d3ff0e 100644
--- a/ext/fg/js/source.js
+++ b/ext/fg/js/source.js
@@ -25,14 +25,16 @@ const IGNORE_TEXT_PATTERN = /\u200c/;
  */
 
 class TextSourceRange {
-    constructor(range, content, imposterContainer) {
+    constructor(range, content, imposterContainer, imposterSourceElement) {
         this.range = range;
+        this.rangeStartOffset = range.startOffset;
         this.content = content;
         this.imposterContainer = imposterContainer;
+        this.imposterSourceElement = imposterSourceElement;
     }
 
     clone() {
-        return new TextSourceRange(this.range.cloneRange(), this.content, this.imposterContainer);
+        return new TextSourceRange(this.range.cloneRange(), this.content, this.imposterContainer, this.imposterSourceElement);
     }
 
     cleanup() {
@@ -55,6 +57,7 @@ class TextSourceRange {
     setStartOffset(length) {
         const state = TextSourceRange.seekBackward(this.range.startContainer, this.range.startOffset, length);
         this.range.setStart(state.node, state.offset);
+        this.rangeStartOffset = this.range.startOffset;
         this.content = state.content;
         return length - state.remainder;
     }
@@ -79,7 +82,17 @@ class TextSourceRange {
     }
 
     equals(other) {
-        return other && other.range && other.range.compareBoundaryPoints(Range.START_TO_START, this.range) === 0;
+        if (other === null) {
+            return false;
+        }
+        if (this.imposterSourceElement !== null) {
+            return (
+                this.imposterSourceElement === other.imposterSourceElement &&
+                this.rangeStartOffset === other.rangeStartOffset
+            );
+        } else {
+            return this.range.compareBoundaryPoints(Range.START_TO_START, other.range) === 0;
+        }
     }
 
     static shouldEnter(node) {