diff --git a/src/calibre/gui2/tweak_book/diff/view.py b/src/calibre/gui2/tweak_book/diff/view.py
index 661ff816b6..64de1fa5a8 100644
--- a/src/calibre/gui2/tweak_book/diff/view.py
+++ b/src/calibre/gui2/tweak_book/diff/view.py
@@ -925,16 +925,18 @@ class DiffView(QWidget):  # {{{
         self.resize_timer = QTimer(self)
         self.resize_timer.setSingleShot(True)
         self.resize_timer.timeout.connect(self.resize_debounced)
-        for i, bar in enumerate((self.scrollbar, self.view.left.verticalScrollBar(), self.view.right.verticalScrollBar())):
+        for bar in (self.scrollbar, self.view.left.verticalScrollBar(), self.view.right.verticalScrollBar()):
             self.bars.append(bar)
-            bar.valueChanged[int].connect(partial(self.scrolled, i))
+            bar.scroll_idx = len(self.bars) - 1
+            connect_lambda(bar.valueChanged[int], self, lambda self: self.scrolled(self.sender().scroll_idx))
         self.view.left.resized.connect(self.resized)
-        for i, v in enumerate((self.view.left, self.view.right, self.view.handle(1))):
+        for v in (self.view.left, self.view.right, self.view.handle(1)):
             v.wheel_event.connect(self.scrollbar.wheelEvent)
-            if i < 2:
+            if v is self.view.left or v is self.view.right:
                 v.next_change.connect(self.next_change)
                 v.line_activated.connect(self.line_activated)
-                v.scrolled.connect(partial(self.scrolled, i + 1))
+                connect_lambda(v.scrolled, self,
+                        lambda self: self.scrolled(1 if self.sender() is self.view.left else 2))
 
     def next_change(self, delta):
         assert delta in (1, -1)
@@ -1093,4 +1095,3 @@ class DiffView(QWidget):  # {{{
             return True
         return False
 # }}}
-
diff --git a/src/calibre/gui2/tweak_book/editor/image.py b/src/calibre/gui2/tweak_book/editor/image.py
index 616ca3153c..cb9bbf71e3 100644
--- a/src/calibre/gui2/tweak_book/editor/image.py
+++ b/src/calibre/gui2/tweak_book/editor/image.py
@@ -7,7 +7,6 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import sys
-from functools import partial
 
 from PyQt5.Qt import (
     QMainWindow, Qt, QApplication, pyqtSignal, QLabel, QIcon, QFormLayout, QSize,
@@ -40,8 +39,8 @@ class ResizeDialog(QDialog):  # {{{
         h.setValue(height)
         h.setSuffix(' px')
         l.addRow(_('&Height:'), h)
-        w.valueChanged.connect(partial(self.keep_ar, 'width'))
-        h.valueChanged.connect(partial(self.keep_ar, 'height'))
+        connect_lambda(w.valueChanged, self, lambda self: self.keep_ar('width'))
+        connect_lambda(h.valueChanged, self, lambda self: self.keep_ar('height'))
 
         self.ar = ar = QCheckBox(_('Keep &aspect ratio'))
         ar.setChecked(True)
@@ -350,5 +349,6 @@ def launch_editor(path_to_edit, path_is_raw=False):
     t.show()
     app.exec_()
 
+
 if __name__ == '__main__':
     launch_editor(sys.argv[-1])
diff --git a/src/calibre/gui2/tweak_book/editor/insert_resource.py b/src/calibre/gui2/tweak_book/editor/insert_resource.py
index 86d7620440..a846c4b5b2 100644
--- a/src/calibre/gui2/tweak_book/editor/insert_resource.py
+++ b/src/calibre/gui2/tweak_book/editor/insert_resource.py
@@ -259,14 +259,21 @@ class InsertImage(Dialog):
             self.preserve_aspect_ratio = a = QCheckBox(_('Preserve aspect ratio'))
             a.setToolTip(_('Preserve the aspect ratio of the inserted image when rendering it full paged'))
             a.setChecked(tprefs['preserve_aspect_ratio_when_inserting_image'])
-            f.toggled.connect(lambda : (tprefs.set('insert_full_screen_image', f.isChecked()), a.setVisible(f.isChecked())))
-            a.toggled.connect(lambda : tprefs.set('preserve_aspect_ratio_when_inserting_image', a.isChecked()))
+            f.toggled.connect(self.full_page_image_toggled)
+            a.toggled.connect(self.par_toggled)
             a.setVisible(f.isChecked())
             h = QHBoxLayout()
             l.addLayout(h, 3, 0, 1, -1)
             h.addWidget(f), h.addStretch(10), h.addWidget(a)
         l.addWidget(self.bb, 4, 0, 1, 2)
 
+    def full_page_image_toggled(self):
+        tprefs.set('insert_full_screen_image', self.fullpage.isChecked())
+        self.preserve_aspect_ratio.setVisible(self.fullpage.isChecked())
+
+    def par_toggled(self):
+        tprefs.set('preserve_aspect_ratio_when_inserting_image', self.preserve_aspect_ratio.isChecked())
+
     def refresh(self):
         self.d.cover_cache.clear()
         self.model.refresh()
@@ -439,9 +446,9 @@ class NewBook(Dialog):  # {{{
         bb.clear()
         bb.addButton(bb.Cancel)
         b = bb.addButton('&EPUB', bb.AcceptRole)
-        b.clicked.connect(partial(self.set_fmt, 'epub'))
+        connect_lambda(b.clicked, self, lambda self: self.set_fmt('epub'))
         b = bb.addButton('&AZW3', bb.AcceptRole)
-        b.clicked.connect(partial(self.set_fmt, 'azw3'))
+        connect_lambda(b.clicked, self, lambda self: self.set_fmt('azw3'))
 
     def set_fmt(self, fmt):
         self.fmt = fmt