Changed theme switching, probably fixes #509 as well

data/dark/style.css

@@ -1,6 +1,6 @@
 #main_window
 {
-    background-image: url(background.png);
+    background-image: url(:/icons/dark_background.png);
 }
 
 #address_input[readOnly=true], #amount_input[readOnly=true]

gui/qt/lite_window.py

@@ -348,12 +348,10 @@ class MiniWindow(QDialog):
 
 
     def toggle_theme(self, theme_name):
-        old_path = QDir.currentPath()
         self.actuator.change_theme(theme_name)
         # Recompute style globally
         qApp.style().unpolish(self)
         qApp.style().polish(self)
-        QDir.setCurrent(old_path)
 
     def closeEvent(self, event):
         g = self.geometry()
@@ -659,7 +657,6 @@ class MiniActuator:
         self.g = main_window
         self.theme_name = self.g.config.get('litegui_theme','Cleanlook')
         self.themes = load_theme_paths()
-        # see issue 509
         self.load_theme()
 
     def load_theme(self):
@@ -669,8 +666,8 @@ class MiniActuator:
         except KeyError:
             util.print_error("Theme not found!", self.theme_name)
             return
-        full_theme_path = ("%s/%s/style.css" % (theme_prefix, theme_path))
-        with open(rsrc(full_theme_path)) as style_file:
+        full_theme_path = "%s/%s/style.css" % (theme_prefix, theme_path)
+        with open(full_theme_path) as style_file:
             qApp.setStyleSheet(style_file.read())
 
     def theme_names(self):

gui/qt/main_window.py

@@ -221,19 +221,12 @@ class ElectrumWindow(QMainWindow):
 
         actuator = lite_window.MiniActuator(self)
 
-        # Should probably not modify the current path but instead
-        # change the behaviour of rsrc(...)
-        old_path = QDir.currentPath()
         actuator.load_theme()
 
         self.mini = lite_window.MiniWindow(actuator, self.go_full, self.config)
 
         driver = lite_window.MiniDriver(self, self.mini)
 
-        # Reset path back to original value now that loading the GUI
-        # is completed.
-        QDir.setCurrent(old_path)
-
         if self.config.get('lite_mode') is True:
             self.go_lite()
         else:

icons.qrc

@@ -21,5 +21,6 @@
     <file>icons/electrum_dark_icon.png</file>
     <file>icons/unconfirmed.png</file>
     <file>icons/network.png</file>
+    <file>icons/dark_background.png</file>
   </qresource>
 </RCC>