diff --git a/app/client/widgets/TextEditor.css b/app/client/widgets/TextEditor.css
index 51bc61f2..60b3b240 100644
--- a/app/client/widgets/TextEditor.css
+++ b/app/client/widgets/TextEditor.css
@@ -97,14 +97,16 @@
 
 .error_msg {
   color: black;
-  cursor: default;
-  margin: 4px;
+  cursor: pointer;
+  padding: 4px;
 }
 
 .error_details {
   padding: 2px 2px 2px 2px;
   background-color: #F8ECEA;
   margin: 0 0 -2px 0;
+  font-family: 'Monaco', 'Menlo', monospace;
+  font-size: 12px;
 }
 
 .error_box {
diff --git a/sandbox/grist/codebuilder.py b/sandbox/grist/codebuilder.py
index a58f5865..b5764af8 100644
--- a/sandbox/grist/codebuilder.py
+++ b/sandbox/grist/codebuilder.py
@@ -118,10 +118,11 @@ def _create_syntax_error_code(builder, input_text, err):
   output_offset = output_ln.line_to_offset(err.lineno, err.offset - 1 if err.offset else 0)
   input_offset = builder.map_back_offset(output_offset)
   line, col = input_ln.offset_to_line(input_offset)
-  message = '%s on line %d col %d' % (err.args[0], line, col + 1)
-  return "%s\nraise %s(%r)" % (
+  message = err.args[0]
+  input_text_line = input_text.splitlines()[line - 1]
+  return "%s\nraise %s(%r, ('usercode', %r, %r, %r))" % (
     textbuilder.line_start_re.sub('# ', input_text.rstrip()),
-    type(err).__name__, message)
+    type(err).__name__, message, line, col + 1, input_text_line)
 
 #----------------------------------------------------------------------
 
diff --git a/sandbox/grist/test_codebuilder.py b/sandbox/grist/test_codebuilder.py
index 0fa00f95..401bcf4d 100644
--- a/sandbox/grist/test_codebuilder.py
+++ b/sandbox/grist/test_codebuilder.py
@@ -4,6 +4,7 @@ import unittest
 import codebuilder
 import six
 
+unicode_prefix = 'u' if six.PY2 else ''
 
 def make_body(formula, default=None):
   return codebuilder.make_formula_body(formula, default).get_text()
@@ -72,14 +73,20 @@ class TestCodeBuilder(unittest.TestCase):
 
     # Test that we produce valid code when "$foo" occurs in invalid places.
     self.assertEqual(make_body('foo($bar=1)'),
-                     "# foo($bar=1)\nraise SyntaxError('invalid syntax on line 1 col 5')")
+                     "# foo($bar=1)\n"
+                     "raise SyntaxError('invalid syntax', ('usercode', 1, 5, %s'foo($bar=1)'))"
+                     % unicode_prefix)
     self.assertEqual(make_body('def $bar(): pass'),
-                     "# def $bar(): pass\nraise SyntaxError('invalid syntax on line 1 col 5')")
+                     "# def $bar(): pass\n"
+                     "raise SyntaxError('invalid syntax', ('usercode', 1, 5, %s'def $bar(): pass'))"
+                     % unicode_prefix)
 
     # If $ is a syntax error, we don't want to turn it into a different syntax error.
     self.assertEqual(make_body('$foo + ("$%.2f" $ ($17.5))'),
                      '# $foo + ("$%.2f" $ ($17.5))\n'
-                     "raise SyntaxError('invalid syntax on line 1 col 17')")
+                     "raise SyntaxError('invalid syntax', "
+                     "('usercode', 1, 17, {}'$foo + (\"$%.2f\" $ ($17.5))'))"
+                     .format(unicode_prefix))
     self.assertEqual(make_body('if $foo:\n' +
                                '  return $foo\n' +
                                'else:\n' +
@@ -88,17 +95,21 @@ class TestCodeBuilder(unittest.TestCase):
                      '#   return $foo\n' +
                      '# else:\n' +
                      '#   return $ bar\n' +
-                     "raise SyntaxError('invalid syntax on line 4 col 10')")
+                     "raise SyntaxError('invalid syntax', ('usercode', 4, 10, %s'  return $ bar'))"
+                     % unicode_prefix)
 
     # Check for reasonable behaviour with non-empty text and no statements.
     self.assertEqual(make_body('# comment'), '# comment\npass')
 
     self.assertEqual(make_body('rec = 1'), "# rec = 1\n" +
                      "raise SyntaxError('Grist disallows assignment " +
-                     "to the special variable \"rec\" on line 1 col 1')")
+                     "to the special variable \"rec\"', ('usercode', 1, 1, %s'rec = 1'))"
+                     % unicode_prefix)
     self.assertEqual(make_body('for rec in []: pass'), "# for rec in []: pass\n" +
                      "raise SyntaxError('Grist disallows assignment " +
-                     "to the special variable \"rec\" on line 1 col 4')")
+                     "to the special variable \"rec\"', "
+                     "('usercode', 1, 4, %s'for rec in []: pass'))"
+                     % unicode_prefix)
 
     # some legitimates use of rec
     body = ("""
@@ -124,8 +135,10 @@ return rec
 """)
 
     self.assertRegex(make_body(body),
-                             r"raise SyntaxError\('Grist disallows assignment" +
-                             r" to the special variable \"rec\" on line 4 col 7'\)")
+                     r"raise SyntaxError\('Grist disallows assignment" +
+                     r" to the special variable \"rec\"', "
+                     r"\('usercode', 4, 7, %s'\[1 for rec in \[\]\]'\)\)"
+                     % unicode_prefix)
 
 
   def test_make_formula_body_unicode(self):
diff --git a/sandbox/grist/test_formula_error.py b/sandbox/grist/test_formula_error.py
index 3116eb3b..f97ef30b 100644
--- a/sandbox/grist/test_formula_error.py
+++ b/sandbox/grist/test_formula_error.py
@@ -76,10 +76,36 @@ else:
                             ))
 
     self.assertFormulaError(self.engine.get_formula_error('Math', 'syntax_err', 3),
-                            SyntaxError, "invalid syntax on line 5 col 9")
+                            SyntaxError, "invalid syntax (usercode, line 5)",
+                            textwrap.dedent(
+                              r"""
+                                File "usercode", line 5
+                                  return: 0
+                                        \^
+                              SyntaxError: invalid syntax
+                              """
+                            ))
 
+    if six.PY2:
+      traceback_regex = textwrap.dedent(
+        r"""
+          File "usercode", line 2
+            if sum\(3, 5\) > 6:
+            \^
+        IndentationError: unexpected indent
+        """
+      )
+    else:
+      traceback_regex = textwrap.dedent(
+        r"""
+          File "usercode", line 2
+            if sum\(3, 5\) > 6:
+        IndentationError: unexpected indent
+        """
+      )
     self.assertFormulaError(self.engine.get_formula_error('Math', 'indent_err', 3),
-                            IndentationError, "unexpected indent on line 2 col 2")
+                            IndentationError, 'unexpected indent (usercode, line 2)',
+                            traceback_regex)
 
     self.assertFormulaError(self.engine.get_formula_error('Math', 'other_err', 3),
                             TypeError, "'int' object is not iterable",
diff --git a/sandbox/grist/test_gencode.py b/sandbox/grist/test_gencode.py
index 3c9795c5..218e4128 100644
--- a/sandbox/grist/test_gencode.py
+++ b/sandbox/grist/test_gencode.py
@@ -4,6 +4,7 @@ import unittest
 import difflib
 import re
 
+import six
 from six.moves import xrange
 
 import gencode
@@ -69,6 +70,11 @@ class TestGenCode(unittest.TestCase):
     gcode = gencode.GenCode()
     gcode.make_module(self.schema)
     generated = gcode.get_user_text()
+    if six.PY3:
+      generated = generated.replace(
+         ", 'for a in b'))",
+        ", u'for a in b'))",
+      )
     self.assertEqual(generated, saved_sample, "Generated code doesn't match sample:\n" +
                      "".join(difflib.unified_diff(generated.splitlines(True),
                                                   saved_sample.splitlines(True),
diff --git a/sandbox/grist/usercode.py b/sandbox/grist/usercode.py
index 9b1c4f1b..b9e20d71 100644
--- a/sandbox/grist/usercode.py
+++ b/sandbox/grist/usercode.py
@@ -63,6 +63,6 @@ class Address:
   def badSyntax(rec, table):
     # for a in b
     # 10
-    raise SyntaxError('invalid syntax on line 1 col 11')
+    raise SyntaxError('invalid syntax', ('usercode', 1, 11, u'for a in b'))
 ======================================================================
 """