diff --git a/static/messages.js b/static/messages.js
index 6f1e6cd0..f92f6554 100644
--- a/static/messages.js
+++ b/static/messages.js
@@ -486,11 +486,17 @@ function _markdownTableCopyPayloadForTable(table){
   if(!table||!table.rows) return null;
   const rows=Array.from(table.rows||[]);
   if(!rows.length) return null;
+  let headerRowCount=0;
+  while(headerRowCount<rows.length){
+    const cells=Array.from(rows[headerRowCount].cells||[]);
+    if(!cells.length||!cells.every((cell)=>cell&&cell.tagName==='TH')) break;
+    headerRowCount++;
+  }
 
-  const htmlRows=rows.map((row)=>{
+  const renderRows=(rowSet)=>rowSet.map((row)=>{
     const cellTag=(cell)=>String(cell&&cell.tagName?cell.tagName.toLowerCase():'td');
     const cells=Array.from(row.cells||[])
-      .filter((cell)=>cell&&cell.nodeType===1 || cell&&cell.nodeType===3)
+      .filter((cell)=>cell&&cell.nodeType===1)
       .map((cell)=>{
         const tag=cellTag(cell);
         const text=_sanitizeMarkdownTableCellText(cell);
@@ -499,6 +505,12 @@ function _markdownTableCopyPayloadForTable(table){
       .join('');
     return `<tr>${cells}</tr>`;
   }).join('');
+  const headerRows=headerRowCount?renderRows(rows.slice(0, headerRowCount)):'';
+  const bodyRows=renderRows(rows.slice(headerRowCount));
+  const tableSections=[
+    headerRows?`<thead>${headerRows}</thead>`:'',
+    bodyRows?`<tbody>${bodyRows}</tbody>`:'',
+  ].join('');
 
   const plainRows=rows.map((row)=>{
     return Array.from(row.cells||[])
@@ -506,7 +518,7 @@ function _markdownTableCopyPayloadForTable(table){
       .join('\t');
   }).join('\n');
 
-  return {html:`<table>${htmlRows}</table>`, plain:plainRows};
+  return {html:`<table>${tableSections}</table>`, plain:plainRows};
 }
 
 function _findEnhancedMarkdownTable(node){
@@ -518,6 +530,15 @@ function _findEnhancedMarkdownTable(node){
   return null;
 }
 
+function _findMarkdownTableCell(node){
+  let current=node&&node.nodeType===3?node.parentElement:node;
+  while(current){
+    if(current.matches&&current.matches('th,td')) return current;
+    current=current.parentElement||current.parentNode;
+  }
+  return null;
+}
+
 function _findEnhancedMarkdownTableFromRange(range){
   if(!range) return null;
   const found=_findEnhancedMarkdownTable(range.startContainer)
@@ -543,6 +564,9 @@ function _handleMarkdownTableCopy(event){
   if(!selection||selection.isCollapsed||!selection.rangeCount) return;
   const range=selection.getRangeAt(0);
   if(!range) return;
+  const startCell=_findMarkdownTableCell(range.startContainer);
+  const endCell=_findMarkdownTableCell(range.endContainer);
+  if(startCell&&endCell&&startCell===endCell) return;
   const table=_findEnhancedMarkdownTableFromRange(range);
   if(!table||!table.matches||!table.matches('table[data-markdown-table-enhanced]')) return;
   const payload=_markdownTableCopyPayloadForTable(table);
diff --git a/tests/test_issue4945_markdown_table_copy.py b/tests/test_issue4945_markdown_table_copy.py
index 3d94a803..ae7b1dfc 100644
--- a/tests/test_issue4945_markdown_table_copy.py
+++ b/tests/test_issue4945_markdown_table_copy.py
@@ -24,15 +24,53 @@ function extractFunc(name) {
   const re = new RegExp('function\\s+' + name + '\\s*\\(');
   const start = src.search(re);
   if (start < 0) throw new Error(name + ' not found');
-  let i = src.indexOf('{', start);
-  let depth = 1;
-  i++;
-  while (depth > 0 && i < src.length) {
-    if (src[i] === '{') depth++;
-    else if (src[i] === '}') depth--;
-    i++;
+  const braceStart = src.indexOf('{', start);
+  let depth = 0;
+  let inString = null;
+  let escaped = false;
+  let inLineComment = false;
+  let inBlockComment = false;
+  for (let i = braceStart; i < src.length; i++) {
+    const ch = src[i];
+    const next = i + 1 < src.length ? src[i + 1] : '';
+    if (inLineComment) {
+      if (ch === '\n') inLineComment = false;
+      continue;
+    }
+    if (inBlockComment) {
+      if (ch === '*' && next === '/') {
+        inBlockComment = false;
+        i++;
+      }
+      continue;
+    }
+    if (inString) {
+      if (escaped) escaped = false;
+      else if (ch === '\\') escaped = true;
+      else if (ch === inString) inString = null;
+      continue;
+    }
+    if (ch === '/' && next === '/') {
+      inLineComment = true;
+      i++;
+      continue;
+    }
+    if (ch === '/' && next === '*') {
+      inBlockComment = true;
+      i++;
+      continue;
+    }
+    if (ch === "'" || ch === '"' || ch === '`') {
+      inString = ch;
+      continue;
+    }
+    if (ch === '{') depth++;
+    else if (ch === '}') {
+      depth--;
+      if (depth === 0) return src.slice(start, i + 1);
+    }
   }
-  return src.slice(start, i);
+  throw new Error(name + ' brace scan failed');
 }
 
 const required = [
@@ -41,6 +79,7 @@ const required = [
   '_markdownTableCellText',
   '_sanitizeMarkdownTableCellText',
   '_findEnhancedMarkdownTable',
+  '_findMarkdownTableCell',
   '_findEnhancedMarkdownTableFromRange',
   '_markdownTableCopyPayloadForTable',
   '_handleMarkdownTableCopy',
@@ -260,6 +299,8 @@ const payload = _markdownTableCopyPayloadForTable(table);
 console.log(JSON.stringify(payload));
 """
     )
+    assert "<thead><tr><th>Product</th><th>Price</th></tr></thead>" in out["html"]
+    assert "<tbody><tr><td>Widget</td><td>12</td></tr></tbody>" in out["html"]
     assert "<th>Product</th>" in out["html"]
     assert "<th>Price</th>" in out["html"]
     assert "markdown-table-sort" not in out["html"]
@@ -434,3 +475,43 @@ console.log(JSON.stringify({ prevented: event.preventDefaultCalled, data: clipbo
     assert out["prevented"] is True
     assert "<th>Product</th>" in out["data"]["text/html"]
     assert out["data"]["text/plain"].startswith("Product\tPrice")
+
+
+def test_single_cell_subselection_leaves_native_copy_unmodified():
+    out = _run_js(
+        """
+const {table, body} = buildEnhancedTableFixture(true);
+
+const range = {
+  startContainer: body.cells[0].children[0],
+  endContainer: body.cells[0].children[0],
+  commonAncestorContainer: body.cells[0],
+};
+
+window.getSelection = () => ({
+  isCollapsed: false,
+  rangeCount: 1,
+  getRangeAt: () => range,
+});
+
+const clipboard = {
+  data: {},
+  setData(type, value) {
+    this.data[type] = value;
+  }
+};
+
+const event = {
+  preventDefaultCalled: false,
+  preventDefault() {
+    this.preventDefaultCalled = true;
+  },
+  clipboardData: clipboard,
+};
+
+_handleMarkdownTableCopy(event);
+console.log(JSON.stringify({ prevented: event.preventDefaultCalled, data: clipboard.data }));
+"""
+    )
+    assert out["prevented"] is False
+    assert out["data"] == {}