Fixed bug #33922

word/Editor/ParagraphContentBase.js

@@ -1649,6 +1649,9 @@ CParagraphContentWithParagraphLikeContent.prototype.Get_ElementByPos = function(
         return this;
 
     var CurPos = ContentPos.Get(Depth);
+    if (!this.Content[CurPos])
+    	return null;
+
     return this.Content[CurPos].Get_ElementByPos(ContentPos, Depth + 1);
 };
 CParagraphContentWithParagraphLikeContent.prototype.Get_PosByDrawing = function(Id, ContentPos, Depth)

word/Math/mathContent.js

@@ -3561,6 +3561,8 @@ CMathContent.prototype.Get_ParaContentPos = function(bSelection, bStart, Content
 	else
 	{
 		var nPos = (true !== bSelection ? this.CurPos : (false !== bStart ? this.Selection.StartPos : this.Selection.EndPos));
+		nPos = Math.max(0, Math.min(nPos, this.Content.length - 1));
+
 		ContentPos.Add(nPos);
 
 		if (undefined !== this.Content[nPos])
@@ -3576,16 +3578,19 @@ CMathContent.prototype.Set_ParaContentPos = function(ContentPos, Depth)
     if (undefined === CurPos || CurPos < 0)
     {
         this.CurPos = 0;
+        if (this.Content[this.CurPos])
         	this.Content[this.CurPos].Cursor_MoveToStartPos();
     }
     else if (CurPos > this.Content.length - 1)
     {
         this.CurPos = this.Content.length - 1;
+        if (this.Content[this.CurPos])
         	this.Content[this.CurPos].Cursor_MoveToEndPos(false);
     }
     else
     {
         this.CurPos = CurPos;
+        if (this.Content[this.CurPos])
         	this.Content[this.CurPos].Set_ParaContentPos(ContentPos, Depth + 1);
     }
 };