diff --git a/src/calibre/gui2/tweak_book/editor/syntax/base.py b/src/calibre/gui2/tweak_book/editor/syntax/base.py
index f0649a7d58..00fe98efbf 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/base.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/base.py
@@ -6,44 +6,53 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
-from PyQt4.Qt import (QSyntaxHighlighter, QApplication, QCursor, Qt)
+import weakref
+
+from PyQt4.Qt import (
+    QTextCursor, pyqtSlot, QTextBlockUserData, QTextLayout)
 
 from ..themes import highlight_to_char_format
+from calibre.gui2.tweak_book.widgets import BusyCursor
 
-class SimpleState(object):
-
-    def __init__(self, value):
-        self.parse = value
-
-    @property
-    def value(self):
-        return self.parse
-
-def run_loop(state, state_map, formats, text):
+def run_loop(user_data, state_map, formats, text):
+    state = user_data.state
     i = 0
     while i < len(text):
-        fmt = state_map[state.parse](state, text, i, formats)
+        fmt = state_map[state.parse](state, text, i, formats, user_data)
         for num, f in fmt:
             yield i, num, f
             i += num
 
-class SyntaxHighlighter(QSyntaxHighlighter):
+class SimpleState(object):
+
+    __slots__ = ('parse',)
+
+    def __init__(self):
+        self.parse = 0
+
+    def copy(self):
+        s = SimpleState()
+        s.parse = self.parse
+        return s
+
+class SimpleUserData(QTextBlockUserData):
+
+    def __init__(self):
+        QTextBlockUserData.__init__(self)
+        self.state = SimpleState()
+
+    def clear(self, state=None):
+        self.state = SimpleState() if state is None else state
+
+class SyntaxHighlighter(object):
 
-    state_map = {0:lambda state, text, i, formats:[(len(text), None)]}
     create_formats_func = lambda highlighter: {}
     spell_attributes = ()
     tag_ok_for_spell = lambda x: False
+    user_data_factory = SimpleUserData
 
-    def __init__(self, *args, **kwargs):
-        QSyntaxHighlighter.__init__(self, *args, **kwargs)
-
-    def create_state(self, num):
-        return SimpleState(max(0, num))
-
-    def rehighlight(self):
-        QApplication.setOverrideCursor(QCursor(Qt.WaitCursor))
-        QSyntaxHighlighter.rehighlight(self)
-        QApplication.restoreOverrideCursor()
+    def __init__(self):
+        self.document_ref = lambda : None
 
     def apply_theme(self, theme):
         self.theme = {k:highlight_to_char_format(v) for k, v in theme.iteritems()}
@@ -53,20 +62,94 @@ class SyntaxHighlighter(QSyntaxHighlighter):
     def create_formats(self):
         self.formats = self.create_formats_func()
 
-    def highlightBlock(self, text):
-        try:
-            state = self.previousBlockState()
-            self.setCurrentBlockUserData(None)  # Ensure that any stale user data is discarded
-            state = self.create_state(state)
-            state.get_user_data, state.set_user_data = self.currentBlockUserData, self.setCurrentBlockUserData
-            for i, num, fmt in run_loop(state, self.state_map, self.formats, unicode(text)):
-                if fmt is not None:
-                    self.setFormat(i, num, fmt)
-            self.setCurrentBlockState(state.value)
-        except:
-            import traceback
-            traceback.print_exc()
-        finally:
-            # Disabled as it causes crashes
-            pass  # QApplication.processEvents()  # Try to keep the editor responsive to user input
+    def set_document(self, doc):
+        old_doc = self.document_ref()
+        if old_doc is not None:
+            old_doc.contentsChange.disconnect(self.reformat_blocks)
+            c = QTextCursor(old_doc)
+            c.beginEditBlock()
+            blk = old_doc.begin()
+            while blk.isValid():
+                blk.layout().clearAdditionalFormats()
+                blk = blk.next()
+            c.endEditBlock()
+        if doc is not None:
+            self.document_ref = weakref.ref(doc)
+            doc.contentsChange.connect(self.reformat_blocks)
+            self.rehighlight()
+        else:
+            self.document_ref = lambda : None
+
+    def rehighlight(self):
+        doc = self.document_ref()
+        if doc is None:
+            return
+        lb = doc.lastBlock()
+        with BusyCursor():
+            self.reformat_blocks(0, 0, lb.position() + lb.length())
+
+    def get_user_data(self, block):
+        ud = block.userData()
+        new_data = False
+        if ud is None:
+            ud = self.user_data_factory()
+            block.setUserData(ud)
+            new_data = True
+        return ud, new_data
+
+    @pyqtSlot(int, int, int)
+    def reformat_blocks(self, position, removed, added):
+        doc = self.document_ref()
+        if doc is None:
+            return
+        last_block = doc.findBlock(position + added + (1 if removed > 0 else 0))
+        if not last_block.isValid():
+            last_block = doc.lastBlock()
+        end_pos = last_block.position() + last_block.length()
+        force_next_highlight = False
+
+        doc.contentsChange.disconnect(self.reformat_blocks)
+        try:
+            block = doc.findBlock(position)
+            while block.isValid() and (block.position() < end_pos or force_next_highlight):
+                ud, new_ud = self.get_user_data(block)
+                orig_state = ud.state
+                pblock = block.previous()
+                if pblock.isValid():
+                    start_state = pblock.userData()
+                    if start_state is None:
+                        start_state = self.user_data_factory().state
+                    else:
+                        start_state = start_state.state.copy()
+                else:
+                    start_state = self.user_data_factory().state
+                ud.clear(state=start_state)  # Ensure no stale user data lingers
+                formats = []
+                for i, num, fmt in run_loop(ud, self.state_map, self.formats, unicode(block.text())):
+                    if fmt is not None:
+                        formats.append((i, num, fmt))
+                self.apply_format_changes(doc, block, formats)
+                force_next_highlight = new_ud or ud.state != orig_state
+                block = block.next()
+        finally:
+            doc.contentsChange.connect(self.reformat_blocks)
+
+    def apply_format_changes(self, doc, block, formats):
+        layout = block.layout()
+        preedit_start = layout.preeditAreaPosition()
+        preedit_length = layout.preeditAreaText().length()
+        ranges = []
+        R = QTextLayout.FormatRange
+        for i, num, fmt in formats:
+            # Adjust range by pre-edit text, if any
+            if preedit_start != 0:
+                if i >= preedit_start:
+                    i += preedit_length
+                elif i + num >= preedit_start:
+                    num += preedit_length
+            r = R()
+            r.start, r.length, r.format = i, num, fmt
+            ranges.append(r)
+        layout.setAdditionalFormats(ranges)
+        doc.markContentsDirty(block.position(), block.length())
 
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/css.py b/src/calibre/gui2/tweak_book/editor/syntax/css.py
index 04c9182b70..7e19790516 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/css.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/css.py
@@ -8,6 +8,8 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import re
 
+from PyQt4.Qt import QTextBlockUserData
+
 from calibre.gui2.tweak_book.editor import SyntaxTextCharFormat
 from calibre.gui2.tweak_book.editor.syntax.base import SyntaxHighlighter
 
@@ -118,41 +120,63 @@ content_tokens = [(re.compile(k), v, n) for k, v, n in [
 
 ]]
 
-class State(object):
+NORMAL = 0
+IN_COMMENT_NORMAL = 1
+IN_SQS = 2
+IN_DQS = 3
+IN_CONTENT = 4
+IN_COMMENT_CONTENT = 5
 
-    NORMAL = 0
-    IN_COMMENT_NORMAL = 1
-    IN_SQS = 2
-    IN_DQS = 3
-    IN_CONTENT = 4
-    IN_COMMENT_CONTENT = 5
+class CSSState(object):
 
-    def __init__(self, num):
-        self.parse  = num & 0b1111
-        self.blocks = num >> 4
+    __slots__ = ('parse', 'blocks')
 
-    @property
-    def value(self):
-        return ((self.parse & 0b1111) | (max(0, self.blocks) << 4))
+    def __init__(self):
+        self.parse  = NORMAL
+        self.blocks = 0
 
+    def copy(self):
+        s = CSSState()
+        s.parse, s.blocks = self.parse, self.blocks
+        return s
 
-def normal(state, text, i, formats):
+    def __eq__(self, other):
+        return self.parse == getattr(other, 'parse', -1) and \
+            self.blocks == getattr(other, 'blocks', -1)
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    def __repr__(self):
+        return "CSSState(parse=%s, blocks=%s)" % (self.parse, self.blocks)
+    __str__ = __repr__
+
+class CSSUserData(QTextBlockUserData):
+
+    def __init__(self):
+        QTextBlockUserData.__init__(self)
+        self.state = CSSState()
+
+    def clear(self, state=None):
+        self.state = CSSState() if state is None else state
+
+def normal(state, text, i, formats, user_data):
     ' The normal state (outside content blocks {})'
     m = space_pat.match(text, i)
     if m is not None:
         return [(len(m.group()), None)]
     cdo = cdo_pat.match(text, i)
     if cdo is not None:
-        state.parse = State.IN_COMMENT_NORMAL
+        state.parse = IN_COMMENT_NORMAL
         return [(len(cdo.group()), formats['comment'])]
     if text[i] == '"':
-        state.parse = State.IN_DQS
+        state.parse = IN_DQS
         return [(1, formats['string'])]
     if text[i] == "'":
-        state.parse = State.IN_SQS
+        state.parse = IN_SQS
         return [(1, formats['string'])]
     if text[i] == '{':
-        state.parse = State.IN_CONTENT
+        state.parse = IN_CONTENT
         state.blocks += 1
         return [(1, formats['bracket'])]
     for token, fmt, name in sheet_tokens:
@@ -162,24 +186,24 @@ def normal(state, text, i, formats):
 
     return [(len(text) - i, formats['unknown-normal'])]
 
-def content(state, text, i, formats):
+def content(state, text, i, formats, user_data):
     ' Inside content blocks '
     m = space_pat.match(text, i)
     if m is not None:
         return [(len(m.group()), None)]
     cdo = cdo_pat.match(text, i)
     if cdo is not None:
-        state.parse = State.IN_COMMENT_CONTENT
+        state.parse = IN_COMMENT_CONTENT
         return [(len(cdo.group()), formats['comment'])]
     if text[i] == '"':
-        state.parse = State.IN_DQS
+        state.parse = IN_DQS
         return [(1, formats['string'])]
     if text[i] == "'":
-        state.parse = State.IN_SQS
+        state.parse = IN_SQS
         return [(1, formats['string'])]
     if text[i] == '}':
         state.blocks -= 1
-        state.parse = State.NORMAL if state.blocks < 1 else State.IN_CONTENT
+        state.parse = NORMAL if state.blocks < 1 else IN_CONTENT
         return [(1, formats['bracket'])]
     if text[i] == '{':
         state.blocks += 1
@@ -191,34 +215,34 @@ def content(state, text, i, formats):
 
     return [(len(text) - i, formats['unknown-normal'])]
 
-def comment(state, text, i, formats):
+def comment(state, text, i, formats, user_data):
     ' Inside a comment '
     pos = text.find('*/', i)
     if pos == -1:
         return [(len(text), formats['comment'])]
-    state.parse = State.NORMAL if state.parse == State.IN_COMMENT_NORMAL else State.IN_CONTENT
+    state.parse = NORMAL if state.parse == IN_COMMENT_NORMAL else IN_CONTENT
     return [(pos - i + 2, formats['comment'])]
 
-def in_string(state, text, i, formats):
+def in_string(state, text, i, formats, user_data):
     'Inside a string'
-    q = '"' if state.parse == State.IN_DQS else "'"
+    q = '"' if state.parse == IN_DQS else "'"
     pos = text.find(q, i)
     if pos == -1:
         if text[-1] == '\\':
             # Multi-line string
             return [(len(text) - i, formats['string'])]
-        state.parse = (State.NORMAL if state.blocks < 1 else State.IN_CONTENT)
+        state.parse = (NORMAL if state.blocks < 1 else IN_CONTENT)
         return [(len(text) - i, formats['unterminated-string'])]
-    state.parse = (State.NORMAL if state.blocks < 1 else State.IN_CONTENT)
+    state.parse = (NORMAL if state.blocks < 1 else IN_CONTENT)
     return [(pos - i + len(q), formats['string'])]
 
 state_map = {
-    State.NORMAL:normal,
-    State.IN_COMMENT_NORMAL: comment,
-    State.IN_COMMENT_CONTENT: comment,
-    State.IN_SQS: in_string,
-    State.IN_DQS: in_string,
-    State.IN_CONTENT: content,
+    NORMAL:normal,
+    IN_COMMENT_NORMAL: comment,
+    IN_COMMENT_CONTENT: comment,
+    IN_SQS: in_string,
+    IN_DQS: in_string,
+    IN_CONTENT: content,
 }
 
 def create_formats(highlighter):
@@ -252,9 +276,8 @@ class CSSHighlighter(SyntaxHighlighter):
 
     state_map = state_map
     create_formats_func = create_formats
+    user_data_factory = CSSUserData
 
-    def create_state(self, num):
-        return State(max(0, num))
 
 if __name__ == '__main__':
     from calibre.gui2.tweak_book.editor.widget import launch_editor
diff --git a/src/calibre/gui2/tweak_book/editor/syntax/html.py b/src/calibre/gui2/tweak_book/editor/syntax/html.py
index 9583090132..2419e59721 100644
--- a/src/calibre/gui2/tweak_book/editor/syntax/html.py
+++ b/src/calibre/gui2/tweak_book/editor/syntax/html.py
@@ -15,7 +15,8 @@ from PyQt4.Qt import QFont, QTextBlockUserData
 from calibre.ebooks.oeb.polish.spell import html_spell_tags, xml_spell_tags
 from calibre.gui2.tweak_book.editor import SyntaxTextCharFormat
 from calibre.gui2.tweak_book.editor.syntax.base import SyntaxHighlighter, run_loop
-from calibre.gui2.tweak_book.editor.syntax.css import create_formats as create_css_formats, state_map as css_state_map, State as CSSState
+from calibre.gui2.tweak_book.editor.syntax.css import (
+    create_formats as create_css_formats, state_map as css_state_map, CSSState, CSSUserData)
 
 from html5lib.constants import cdataElements, rcdataElements
 
@@ -51,41 +52,33 @@ Attr = namedtuple('Attr', 'offset type data')
 
 class Tag(object):
 
-    __slots__ = ('name', 'bold', 'italic', 'lang', 'hash')
+    __slots__ = ('name', 'bold', 'italic', 'lang')
 
     def __init__(self, name, bold=None, italic=None):
         self.name = name
         self.bold = name in bold_tags if bold is None else bold
         self.italic = name in italic_tags if italic is None else italic
         self.lang = None
-        self.hash = 0
-
-    def __hash__(self):
-        return self.hash
 
     def __eq__(self, other):
         return self.name == getattr(other, 'name', None) and self.lang == getattr(other, 'lang', False)
 
     def copy(self):
         ans = Tag(self.name, self.bold, self.italic)
-        ans.lang, ans.hash = self.lang, self.hash
+        ans.lang = self.lang
         return ans
 
-    def update_hash(self):
-        self.hash = hash((self.name, self.lang))
-
 class State(object):
 
-    __slots__ = ('tag_being_defined', 'tags', 'is_bold', 'is_italic',
-                 'current_lang', 'parse', 'get_user_data', 'set_user_data',
-                 'css_formats', 'stack', 'sub_parser_state', 'default_lang',
-                 'attribute_name',)
+    __slots__ = (
+        'tag_being_defined', 'tags', 'is_bold', 'is_italic', 'current_lang',
+        'parse', 'css_formats', 'sub_parser_state', 'default_lang', 'attribute_name',)
 
     def __init__(self):
         self.tags = []
         self.is_bold = self.is_italic = False
-        self.tag_being_defined = self.current_lang = self.get_user_data = self.set_user_data = \
-            self.css_formats = self.stack = self.sub_parser_state = self.default_lang = self.attribute_name = None
+        self.tag_being_defined = self.current_lang =  self.css_formats = \
+            self.sub_parser_state = self.default_lang = self.attribute_name = None
         self.parse = NORMAL
 
     def copy(self):
@@ -95,17 +88,10 @@ class State(object):
         self.tags = [x.copy() for x in self.tags]
         if self.tag_being_defined is not None:
             self.tag_being_defined = self.tag_being_defined.copy()
+        if self.sub_parser_state is not None:
+            ans.sub_parser_state = self.sub_parser_state.copy()
         return ans
 
-    @property
-    def value(self):
-        if self.tag_being_defined is not None:
-            self.tag_being_defined.update_hash()
-        return self.stack.index_for(self)
-
-    def __hash__(self):
-        return hash((self.parse, self.sub_parser_state, self.tag_being_defined, self.attribute_name, tuple(self.tags)))
-
     def __eq__(self, other):
         return (
             self.parse == getattr(other, 'parse', -1) and
@@ -115,6 +101,9 @@ class State(object):
             self.tags == getattr(other, 'tags', None)
         )
 
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
     def open_tag(self, name):
         self.tag_being_defined = Tag(name)
 
@@ -128,7 +117,7 @@ class State(object):
             return  # No matching open tag found, ignore the closing tag
         # Remove all tags upto the matching open tag
         self.tags = self.tags[:-len(removed_tags)]
-        self.sub_parser_state = 0
+        self.sub_parser_state = None
         # Check if we should still be bold or italic
         if self.is_bold:
             self.is_bold = False
@@ -154,71 +143,41 @@ class State(object):
         if self.tag_being_defined is None:
             return
         t, self.tag_being_defined = self.tag_being_defined, None
-        t.update_hash()
         self.tags.append(t)
         self.is_bold = self.is_bold or t.bold
         self.is_italic = self.is_italic or t.italic
         self.current_lang = t.lang or self.current_lang
         if t.name in cdata_tags:
             self.parse = CSS if t.name == 'style' else CDATA
-            self.sub_parser_state = 0
+            self.sub_parser_state = None
 
     def __repr__(self):
         return '<State %s is_bold=%s is_italic=%s current_lang=%s>' % (
             '->'.join(x.name for x in self.tags), self.is_bold, self.is_italic, self.current_lang)
     __str__ = __repr__
 
-class Stack(object):
-
-    ''' Maintain an efficient bi-directional mapping between states and index
-    numbers. Ensures that if state1 == state2 then their corresponding index
-    numbers are the same and vice versa. This is need so that the state number
-    passed to Qt does not change unless the underlying state has actually
-    changed. '''
-
-    def __init__(self):
-        self.index_map = []
-        self.state_map = {}
-
-    def index_for(self, state):
-        ans = self.state_map.get(state, None)
-        if ans is None:
-            self.state_map[state] = ans = len(self.index_map)
-            self.index_map.append(state)
-        return ans
-
-    def state_for(self, index):
-        try:
-            return self.index_map[index]
-        except IndexError:
-            return None
-
 class HTMLUserData(QTextBlockUserData):
 
     def __init__(self):
         QTextBlockUserData.__init__(self)
         self.tags = []
         self.attributes = []
+        self.state = State()
+        self.css_user_data = None
 
-def add_tag_data(state, tag):
-    ud = q = state.get_user_data()
-    if ud is None:
-        ud = HTMLUserData()
-    ud.tags.append(tag)
-    if q is None:
-        state.set_user_data(ud)
+    def clear(self, state=None):
+        self.tags, self.attributes = [], []
+        self.state = State() if state is None else state
+
+def add_tag_data(user_data, tag):
+    user_data.tags.append(tag)
 
 ATTR_NAME, ATTR_VALUE, ATTR_START, ATTR_END = object(), object(), object(), object()
 
-def add_attr_data(state, data_type, data, offset):
-    ud = q = state.get_user_data()
-    if ud is None:
-        ud = HTMLUserData()
-    ud.attributes.append(Attr(offset, data_type, data))
-    if q is None:
-        state.set_user_data(ud)
+def add_attr_data(user_data, data_type, data, offset):
+    user_data.attributes.append(Attr(offset, data_type, data))
 
-def css(state, text, i, formats):
+def css(state, text, i, formats, user_data):
     ' Inside a <style> tag '
     pat = cdata_close_pats['style']
     m = pat.search(text, i)
@@ -227,18 +186,18 @@ def css(state, text, i, formats):
     else:
         css_text = text[i:m.start()]
     ans = []
-    css_state = CSSState(state.sub_parser_state)
-    for j, num, fmt in run_loop(css_state, css_state_map, state.css_formats, css_text):
+    css_user_data = user_data.css_user_data = user_data.css_user_data or CSSUserData()
+    state.sub_parser_state = css_user_data.state = state.sub_parser_state or CSSState()
+    for j, num, fmt in run_loop(css_user_data, css_state_map, formats['css_sub_formats'], css_text):
         ans.append((num, fmt))
-    state.sub_parser_state = css_state.value
     if m is not None:
-        state.sub_parser_state = 0
+        state.sub_parser_state = None
         state.parse = IN_CLOSING_TAG
-        add_tag_data(state, TagStart(m.start(), '', 'style', True, True))
+        add_tag_data(user_data, TagStart(m.start(), '', 'style', True, True))
         ans.extend([(2, formats['end_tag']), (len(m.group()) - 2, formats['tag_name'])])
     return ans
 
-def cdata(state, text, i, formats):
+def cdata(state, text, i, formats, user_data):
     'CDATA inside tags like <title> or <style>'
     name = state.tags[-1].name
     pat = cdata_close_pats[name]
@@ -248,7 +207,7 @@ def cdata(state, text, i, formats):
         return [(len(text) - i, fmt)]
     state.parse = IN_CLOSING_TAG
     num = m.start() - i
-    add_tag_data(state, TagStart(m.start(), '', name, True, True))
+    add_tag_data(user_data, TagStart(m.start(), '', name, True, True))
     return [(num, fmt), (2, formats['end_tag']), (len(m.group()) - 2, formats['tag_name'])]
 
 def mark_nbsp(state, text, nbsp_format):
@@ -268,7 +227,7 @@ def mark_nbsp(state, text, nbsp_format):
         ans = [(len(text), fmt)]
     return ans
 
-def normal(state, text, i, formats):
+def normal(state, text, i, formats, user_data):
     ' The normal state in between tags '
     ch = text[i]
     if ch == '<':
@@ -303,7 +262,7 @@ def normal(state, text, i, formats):
             ans.append((len(prefix)+1, formats['nsprefix']))
         ans.append((len(name), formats['tag_name']))
         state.parse = IN_CLOSING_TAG if closing else IN_OPENING_TAG
-        add_tag_data(state, TagStart(i, prefix, name, closing, True))
+        add_tag_data(user_data, TagStart(i, prefix, name, closing, True))
         (state.close_tag if closing else state.open_tag)(name)
         return ans
 
@@ -319,7 +278,7 @@ def normal(state, text, i, formats):
     t = normal_pat.search(text, i).group()
     return mark_nbsp(state, t, formats['nbsp'])
 
-def opening_tag(cdata_tags, state, text, i, formats):
+def opening_tag(cdata_tags, state, text, i, formats, user_data):
     'An opening tag, like <a>'
     ch = text[i]
     if ch in space_chars:
@@ -330,24 +289,24 @@ def opening_tag(cdata_tags, state, text, i, formats):
             return [(1, formats['/'])]
         state.parse = NORMAL
         l = len(m.group())
-        add_tag_data(state, TagEnd(i + l - 1, True, False))
+        add_tag_data(user_data, TagEnd(i + l - 1, True, False))
         return [(l, formats['tag'])]
     if ch == '>':
         state.finish_opening_tag(cdata_tags)
-        add_tag_data(state, TagEnd(i, False, False))
+        add_tag_data(user_data, TagEnd(i, False, False))
         return [(1, formats['tag'])]
     m = attribute_name_pat.match(text, i)
     if m is None:
         return [(1, formats['?'])]
     state.parse = ATTRIBUTE_NAME
     attrname = state.attribute_name = m.group()
-    add_attr_data(state, ATTR_NAME, attrname, m.start())
+    add_attr_data(user_data, ATTR_NAME, attrname, m.start())
     prefix, name = attrname.partition(':')[0::2]
     if prefix and name:
         return [(len(prefix) + 1, formats['nsprefix']), (len(name), formats['attr'])]
     return [(len(prefix), formats['attr'])]
 
-def attribute_name(state, text, i, formats):
+def attribute_name(state, text, i, formats, user_data):
     ' After attribute name '
     ch = text[i]
     if ch in space_chars:
@@ -359,7 +318,7 @@ def attribute_name(state, text, i, formats):
     state.parse = IN_OPENING_TAG
     return [(0, None)]
 
-def attribute_value(state, text, i, formats):
+def attribute_value(state, text, i, formats, user_data):
     ' After attribute = '
     ch = text[i]
     if ch in space_chars:
@@ -373,20 +332,20 @@ def attribute_value(state, text, i, formats):
         return [(1, formats['no-attr-value'])]
     return [(len(m.group()), formats['string'])]
 
-def quoted_val(state, text, i, formats):
+def quoted_val(state, text, i, formats, user_data):
     ' A quoted attribute value '
     quote = '"' if state.parse is DQ_VAL else "'"
-    add_attr_data(state, ATTR_VALUE, ATTR_START, i)
+    add_attr_data(user_data, ATTR_VALUE, ATTR_START, i)
     pos = text.find(quote, i)
     if pos == -1:
         num = len(text) - i
     else:
         num = pos - i + 1
         state.parse = IN_OPENING_TAG
-        add_attr_data(state, ATTR_VALUE, ATTR_END, i + num)
+        add_attr_data(user_data, ATTR_VALUE, ATTR_END, i + num)
     return [(num, formats['string'])]
 
-def closing_tag(state, text, i, formats):
+def closing_tag(state, text, i, formats, user_data):
     ' A closing tag like </a> '
     ch = text[i]
     if ch in space_chars:
@@ -399,10 +358,10 @@ def closing_tag(state, text, i, formats):
     ans = [(1, formats['end_tag'])]
     if num > 1:
         ans.insert(0, (num - 1, formats['bad-closing']))
-    add_tag_data(state, TagEnd(pos, False, False))
+    add_tag_data(user_data, TagEnd(pos, False, False))
     return ans
 
-def in_comment(state, text, i, formats):
+def in_comment(state, text, i, formats, user_data):
     ' Comment, processing instruction or doctype '
     end = {IN_COMMENT:'-->', IN_PI:'?>'}.get(state.parse, '>')
     pos = text.find(end, i)
@@ -433,7 +392,7 @@ for x in (SQ_VAL, DQ_VAL):
 xml_state_map = state_map.copy()
 xml_state_map[IN_OPENING_TAG] = partial(opening_tag, set())
 
-def create_formats(highlighter):
+def create_formats(highlighter, add_css=True):
     t = highlighter.theme
     formats = {
         'tag': t['Function'],
@@ -463,6 +422,8 @@ def create_formats(highlighter):
         f.setToolTip(msg)
     f = formats['title'] = SyntaxTextCharFormat()
     f.setFontWeight(QFont.Bold)
+    if add_css:
+        formats['css_sub_formats'] = create_css_formats(highlighter)
     return formats
 
 
@@ -471,18 +432,7 @@ class HTMLHighlighter(SyntaxHighlighter):
     state_map = state_map
     create_formats_func = create_formats
     spell_attributes = ('alt', 'title')
-
-    def create_formats(self):
-        super(HTMLHighlighter, self).create_formats()
-        self.default_state = State()
-        self.default_state.css_formats = create_css_formats(self)
-        self.default_state.stack = Stack()
-
-    def create_state(self, val):
-        if val < 0:
-            return self.default_state.copy()
-        ans = self.default_state.stack.state_for(val) or self.default_state
-        return ans.copy()
+    user_data_factory = HTMLUserData
 
     def tag_ok_for_spell(self, name):
         return name not in html_spell_tags
@@ -491,6 +441,7 @@ class XMLHighlighter(HTMLHighlighter):
 
     state_map = xml_state_map
     spell_attributes = ('opf:file-as',)
+    create_formats_func = partial(create_formats, add_css=False)
 
     def tag_ok_for_spell(self, name):
         return name in xml_spell_tags
diff --git a/src/calibre/gui2/tweak_book/editor/text.py b/src/calibre/gui2/tweak_book/editor/text.py
index fda4d47176..e69cc26ffb 100644
--- a/src/calibre/gui2/tweak_book/editor/text.py
+++ b/src/calibre/gui2/tweak_book/editor/text.py
@@ -135,7 +135,7 @@ class TextEdit(PlainTextEdit):
         self.smarts = NullSmarts(self)
         self.current_cursor_line = None
         self.current_search_mark = None
-        self.highlighter = SyntaxHighlighter(self)
+        self.highlighter = SyntaxHighlighter()
         self.line_number_area = LineNumbers(self)
         self.apply_settings()
         self.setMouseTracking(True)
@@ -206,9 +206,9 @@ class TextEdit(PlainTextEdit):
 
     def load_text(self, text, syntax='html', process_template=False):
         self.syntax = syntax
-        self.highlighter = get_highlighter(syntax)(self)
+        self.highlighter = get_highlighter(syntax)()
         self.highlighter.apply_theme(self.theme)
-        self.highlighter.setDocument(self.document())
+        self.highlighter.set_document(self.document())
         sclass = {'html':HTMLSmarts, 'xml':HTMLSmarts}.get(syntax, None)
         if sclass is not None:
             self.smarts = sclass(self)