diff --git a/app/src/processing/app/syntax/SketchTextAreaEditorKit.java b/app/src/processing/app/syntax/SketchTextAreaEditorKit.java
index b1c03e960..41379ae0b 100644
--- a/app/src/processing/app/syntax/SketchTextAreaEditorKit.java
+++ b/app/src/processing/app/syntax/SketchTextAreaEditorKit.java
@@ -1,5 +1,6 @@
 package processing.app.syntax;
 
+import org.fife.ui.rsyntaxtextarea.RSyntaxDocument;
 import org.fife.ui.rsyntaxtextarea.RSyntaxTextAreaEditorKit;
 import org.fife.ui.rtextarea.RTextArea;
 import org.fife.ui.rtextarea.RecordableTextAction;
@@ -16,7 +17,8 @@ public class SketchTextAreaEditorKit extends RSyntaxTextAreaEditorKit {
   private static final Action[] defaultActions = {
     new DeleteNextWordAction(),
     new DeleteLineToCursorAction(),
-    new SelectWholeLineAction()
+    new SelectWholeLineAction(),
+    new ToggleCommentAction()
   };
 
   @Override
@@ -126,4 +128,103 @@ public class SketchTextAreaEditorKit extends RSyntaxTextAreaEditorKit {
 
   }
 
+  public static class ToggleCommentAction extends RecordableTextAction {
+
+    public ToggleCommentAction() {
+      super(rstaToggleCommentAction);
+    }
+
+    @Override
+    public void actionPerformedImpl(ActionEvent e, RTextArea textArea) {
+
+      if (!textArea.isEditable() || !textArea.isEnabled()) {
+        UIManager.getLookAndFeel().provideErrorFeedback(textArea);
+        return;
+      }
+
+      RSyntaxDocument doc = (RSyntaxDocument) textArea.getDocument();
+      Element map = doc.getDefaultRootElement();
+      Caret c = textArea.getCaret();
+      int dot = c.getDot();
+      int mark = c.getMark();
+      int line1 = map.getElementIndex(dot);
+      int line2 = map.getElementIndex(mark);
+      int start = Math.min(line1, line2);
+      int end = Math.max(line1, line2);
+
+      org.fife.ui.rsyntaxtextarea.Token t = doc.getTokenListForLine(start);
+      int languageIndex = t != null ? t.getLanguageIndex() : 0;
+      String[] startEnd = doc.getLineCommentStartAndEnd(languageIndex);
+
+      if (startEnd == null) {
+        UIManager.getLookAndFeel().provideErrorFeedback(textArea);
+        return;
+      }
+
+      // Don't toggle comment on last line if there is no
+      // text selected on it.
+      if (start != end) {
+        Element elem = map.getElement(end);
+        if (Math.max(dot, mark) == elem.getStartOffset()) {
+          end--;
+        }
+      }
+
+      textArea.beginAtomicEdit();
+      try {
+        boolean add = getDoAdd(doc, map, start, end, startEnd);
+        for (line1 = start; line1 <= end; line1++) {
+          Element elem = map.getElement(line1);
+          handleToggleComment(elem, doc, startEnd, add);
+        }
+      } catch (BadLocationException ble) {
+        ble.printStackTrace();
+        UIManager.getLookAndFeel().provideErrorFeedback(textArea);
+      } finally {
+        textArea.endAtomicEdit();
+      }
+
+    }
+
+    private boolean getDoAdd(Document doc, Element map, int startLine, int endLine, String[] startEnd) throws BadLocationException {
+      boolean doAdd = false;
+      for (int i = startLine; i <= endLine; i++) {
+        Element elem = map.getElement(i);
+        int start = elem.getStartOffset();
+        String t = doc.getText(start, elem.getEndOffset() - start - 1).trim();
+        if (!t.startsWith(startEnd[0]) ||
+          (startEnd[1] != null && !t.endsWith(startEnd[1]))) {
+          doAdd = true;
+          break;
+        }
+      }
+      return doAdd;
+    }
+
+    private void handleToggleComment(Element elem, Document doc, String[] startEnd, boolean add) throws BadLocationException {
+      int start = elem.getStartOffset();
+      int end = elem.getEndOffset() - 1;
+      if (add) {
+        doc.insertString(start, startEnd[0], null);
+        if (startEnd[1] != null) {
+          doc.insertString(end + startEnd[0].length(), startEnd[1], null);
+        }
+      } else {
+        String text = doc.getText(start, elem.getEndOffset() - start - 1);
+        start += text.indexOf(startEnd[0]);
+        doc.remove(start, startEnd[0].length());
+        if (startEnd[1] != null) {
+          int temp = startEnd[1].length();
+          doc.remove(end - startEnd[0].length() - temp, temp);
+        }
+      }
+    }
+
+    @Override
+    public final String getMacroID() {
+      return rstaToggleCommentAction;
+    }
+
+  }
+
 }