diff --git a/src/calibre/ebooks/oeb/polish/parsing.py b/src/calibre/ebooks/oeb/polish/parsing.py
index 790f3ac059..3d505763a1 100644
--- a/src/calibre/ebooks/oeb/polish/parsing.py
+++ b/src/calibre/ebooks/oeb/polish/parsing.py
@@ -613,6 +613,22 @@ else:
     replace_chars = re.compile("([\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?<![\uD800-\uDBFF])[\uDC00-\uDFFF])")
 
 
+def html5_parse(raw, decoder=None, log=None, discard_namespaces=False, line_numbers=True, linenumber_attribute=None, replace_entities=True, fix_newlines=True):
+    if isinstance(raw, bytes):
+        raw = xml_to_unicode(raw)[0] if decoder is None else decoder(raw)
+    if replace_entities:
+        raw = xml_replace_entities(raw)
+    if fix_newlines:
+        raw = raw.replace('\r\n', '\n').replace('\r', '\n')
+    raw = replace_chars.sub('', raw)
+    from html5_parser import parse
+    root = parse(raw, maybe_xhtml=not discard_namespaces, line_number_attr=linenumber_attribute, keep_doctype=False)
+    if (discard_namespaces and root.tag != 'html') or (
+        not discard_namespaces and (root.tag != '{%s}%s' % (namespaces['html'], 'html') or root.prefix)):
+        raise ValueError('Failed to parse correctly, root has tag: %s and prefix: %s' % (root.tag, root.prefix))
+    return root
+
+
 def parse_html5(raw, decoder=None, log=None, discard_namespaces=False, line_numbers=True, linenumber_attribute=None, replace_entities=True, fix_newlines=True):
     if isinstance(raw, bytes):
         raw = xml_to_unicode(raw)[0] if decoder is None else decoder(raw)
diff --git a/src/calibre/ebooks/oeb/polish/tests/parsing.py b/src/calibre/ebooks/oeb/polish/tests/parsing.py
index 64d70348ed..e614bc0881 100644
--- a/src/calibre/ebooks/oeb/polish/tests/parsing.py
+++ b/src/calibre/ebooks/oeb/polish/tests/parsing.py
@@ -12,7 +12,7 @@ from lxml import etree
 from html5lib.constants import cdataElements, rcdataElements
 
 from calibre.ebooks.oeb.polish.tests.base import BaseTest
-from calibre.ebooks.oeb.polish.parsing import parse_html5 as parse
+from calibre.ebooks.oeb.polish.parsing import html5_parse as parse
 from calibre.ebooks.oeb.base import XPath, XHTML_NS, SVG_NS, XLINK_NS
 from calibre.ebooks.oeb.parse_utils import html5_parse
 
diff --git a/src/calibre/gui2/tag_browser/ui.py b/src/calibre/gui2/tag_browser/ui.py
index 3d89d7837c..a87bdd0519 100644
--- a/src/calibre/gui2/tag_browser/ui.py
+++ b/src/calibre/gui2/tag_browser/ui.py
@@ -11,9 +11,9 @@ from functools import partial
 
 from PyQt5.Qt import (
     Qt, QIcon, QWidget, QHBoxLayout, QVBoxLayout, QToolButton, QLabel, QFrame,
-    QTimer, QMenu, QPushButton, QActionGroup, QAction)
+    QTimer, QMenu, QActionGroup, QAction)
 
-from calibre.gui2 import error_dialog, question_dialog
+from calibre.gui2 import error_dialog, question_dialog, gprefs
 from calibre.gui2.widgets import HistoryLineEdit
 from calibre.library.field_metadata import category_icon_map
 from calibre.utils.icu import sort_key
@@ -345,21 +345,17 @@ class TagBrowserWidget(QWidget):  # {{{
     def __init__(self, parent):
         QWidget.__init__(self, parent)
         self.parent = parent
-        self._layout = QVBoxLayout()
-        self.setLayout(self._layout)
+        self._layout = QVBoxLayout(self)
         self._layout.setContentsMargins(0,0,0,0)
 
         # Set up the find box & button
         search_layout = QHBoxLayout()
-        self._layout.addLayout(search_layout)
+        search_layout.setAlignment(Qt.AlignLeft | Qt.AlignBottom)
+        search_layout.setContentsMargins(0, 0, 0, 0)
         self.item_search = HistoryLineEdit(parent)
         self.item_search.setMinimumContentsLength(5)
         self.item_search.setSizeAdjustPolicy(self.item_search.AdjustToMinimumContentsLengthWithIcon)
-        try:
-            self.item_search.lineEdit().setPlaceholderText(
-                                                _('Find item in Tag browser'))
-        except:
-            pass             # Using Qt < 4.7
+        self.item_search.lineEdit().setPlaceholderText(_('Find in Tag browser'))
         self.item_search.setToolTip(_(
         'Search for items. This is a "contains" search; items containing the\n'
         'text anywhere in the name will be found. You can limit the search\n'
@@ -387,9 +383,9 @@ class TagBrowserWidget(QWidget):  # {{{
         ac.triggered.connect(self.search_button.click)
 
         self.expand_button = QToolButton()
-        self.expand_button.setText('-')
+        self.expand_button.setText('▶')
         self.expand_button.setToolTip(_('Collapse all categories'))
-        search_layout.addWidget(self.expand_button)
+        search_layout.insertWidget(0, self.expand_button)
         search_layout.setStretch(0, 10)
         search_layout.setStretch(1, 1)
         search_layout.setStretch(2, 1)
@@ -428,13 +424,22 @@ class TagBrowserWidget(QWidget):  # {{{
         self.not_found_label_timer.setSingleShot(True)
         self.not_found_label_timer.timeout.connect(self.not_found_label_timer_event,
                                                    type=Qt.QueuedConnection)
-
-        parent.alter_tb = l = QPushButton(parent)
-        l.setText(_('Alter Tag browser'))
-        l.setIcon(QIcon(I('tags.png')))
+        self.toggle_search_button = b = QToolButton(self)
+        b.setIcon(QIcon(I('search.png')))
+        b.setCheckable(True)
+        search_layout.insertWidget(1, b)
+        b.setChecked(gprefs.get('tag browser search box visible', False))
+        b.setToolTip(_('Search for items in the Tag browser'))
+        b.toggled.connect(self.update_search_state)
+        parent.alter_tb = l = QToolButton(parent)
+        l.setPopupMode(l.InstantPopup)
+        l.setToolTip(_('Alter Tag browser'))
+        l.setIcon(QIcon(I('config.png')))
         l.m = QMenu()
         l.setMenu(l.m)
-        self._layout.addWidget(l)
+        self._layout.addLayout(search_layout)
+        search_layout.insertWidget(0, l)
+        self.update_search_state()
         ac = QAction(parent)
         parent.addAction(ac)
         parent.keyboard.register_shortcut('tag browser alter',
@@ -493,6 +498,14 @@ class TagBrowserWidget(QWidget):  # {{{
         # self.leak_test_timer.timeout.connect(self.test_for_leak)
         # self.leak_test_timer.start(5000)
 
+    def save_state(self):
+        gprefs.set('tag browser search box visible', self.toggle_search_button.isChecked())
+
+    def update_search_state(self):
+        shown = self.toggle_search_button.isChecked()
+        self.search_button.setVisible(shown)
+        self.item_search.setVisible(shown)
+
     def toggle_item(self):
         self.tags_view.toggle_current_index()
 
diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index f5ded1a069..8af720d5a2 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -890,6 +890,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin,  # {{{
             config.set('main_window_geometry', self.saveGeometry())
             dynamic.set('sort_history', self.library_view.model().sort_history)
             self.save_layout_state()
+            self.stack.tb_widget.save_state()
 
     def quit(self, checked=True, restart=False, debug_on_restart=False,
             confirm_quit=True):