...

src/calibre/gui2/__init__.py

@@ -753,7 +753,10 @@ def setup_styles(self):
             if (islinux or isbsd) and st in ('windows', 'motif', 'cde'):
                 from PyQt4.Qt import QStyleFactory
                 styles = set(map(unicode, QStyleFactory.keys()))
-                if 'Plastique' in styles and os.environ.get('KDE_FULL_SESSION',
+                if 'QtCurve' in styles and os.environ.get('KDE_FULL_SESSION',
+                        False):
+                    self.setStyle('QtCurve')
+                elif 'Plastique' in styles and os.environ.get('KDE_FULL_SESSION',
                         False):
                     self.setStyle('Plastique')
                 elif 'Cleanlooks' in styles:

src/calibre/gui2/preferences/look_feel.py

@@ -6,7 +6,7 @@
 __docformat__ = 'restructuredtext en'
 
 from PyQt4.Qt import (QApplication, QFont, QFontInfo, QFontDialog,
-        QAbstractListModel, Qt, QIcon, QKeySequence)
+        QAbstractListModel, Qt, QIcon, QKeySequence, QStyleFactory)
 
 from calibre.gui2.preferences import ConfigWidgetBase, test_widget, CommaSeparatedList
 from calibre.gui2.preferences.look_feel_ui import Ui_Form
@@ -104,6 +104,11 @@ def genesis(self, gui):
         r('widget_style', gprefs, restart_required=True, choices=
                 [(_('System default'), 'system'), (_('Calibre style'),
                     'calibre')])
+        styles = set(map(unicode, QStyleFactory.keys()))
+        if 'QtCurve' not in styles:
+            # Can happen in linux
+            for x in ('opt', 'label'):
+                getattr(self, x+'_widget_style').setVisible(False)
 
         r('cover_flow_queue_length', config, restart_required=True)
 

src/calibre/gui2/preferences/look_feel.ui

@@ -182,7 +182,7 @@
         </widget>
        </item>
        <item row="0" column="0">
-        <widget class="QLabel" name="label_4">
+        <widget class="QLabel" name="label_widget_style">
          <property name="text">
           <string>User interface &amp;style (needs restart):</string>
          </property>