diff --git a/src/calibre/gui2/dialogs/trim_image.py b/src/calibre/gui2/dialogs/trim_image.py
index ab5bbc8a37..b3c039821d 100644
--- a/src/calibre/gui2/dialogs/trim_image.py
+++ b/src/calibre/gui2/dialogs/trim_image.py
@@ -7,7 +7,22 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import os
 import sys
 
-from qt.core import QCheckBox, QDialog, QDialogButtonBox, QFormLayout, QHBoxLayout, QIcon, QKeySequence, QLabel, QSize, QSpinBox, QDoubleSpinBox, Qt, QToolBar, QVBoxLayout
+from qt.core import (
+    QCheckBox,
+    QDialog,
+    QDialogButtonBox,
+    QDoubleSpinBox,
+    QFormLayout,
+    QHBoxLayout,
+    QIcon,
+    QKeySequence,
+    QLabel,
+    QSize,
+    QSpinBox,
+    Qt,
+    QToolBar,
+    QVBoxLayout,
+)
 
 from calibre.gui2 import gprefs
 from calibre.gui2.tweak_book.editor.canvas import Canvas
@@ -37,11 +52,12 @@ class Region(QDialog):
         h.valueChanged.connect(self.value_changed)
         l.addRow(_('&Height:'), h)
         self.ratio_input = r = QDoubleSpinBox(self)
-        r.setRange(0.0, 5.00), r.setDecimals(2), r.setValue(max_width/max_height), r.setSingleStep(0.01), r.setToolTip('For example, use 0.75 for kindle devices.')
+        r.setRange(0.0, 5.00), r.setDecimals(2), r.setValue(max_width/max_height), r.setSingleStep(0.01)
+        r.setToolTip(_('For example, use 0.75 for kindle devices.'))
         self.m_width = max_width
         self.m_height = max_height
         r.valueChanged.connect(self.aspect_changed)
-        l.addRow(_('&Adjust Aspect Ratio:'), r)
+        l.addRow(_('&Aspect ratio:'), r)
         self.const_aspect = ca = QCheckBox(_('Keep the ratio of width to height fixed'))
         ca.toggled.connect(self.const_aspect_toggled)
         l.addRow(ca)
@@ -57,6 +73,7 @@ class Region(QDialog):
         l.addRow(bb)
         self.resize(self.sizeHint())
         self.current_aspect = width / height
+        self.ratio_input.setEnabled(not self.const_aspect.isChecked())
 
     def aspect_changed(self):
         inp = float(self.ratio_input.value())
@@ -69,6 +86,7 @@ class Region(QDialog):
             self.height_input.setValue(self.m_height)
 
     def const_aspect_toggled(self):
+        self.ratio_input.setEnabled(not self.const_aspect.isChecked())
         if self.const_aspect.isChecked():
             self.current_aspect = self.width_input.value() / self.height_input.value()