Comment 2 for bug 1087150

I think problem with Indicator-Sensors menu translation is in file /indicator-sensors/is-indicator.c lines 159-175 - there is macros N_() used:
 static GtkActionEntry entries[] = { { "Preferences", "application-preferences", N_("Preferences…"), NULL, N_("Preferences"), G_CALLBACK(prefs_action) },
while other lines with translation strings has _() instead of N_(), see for example line 699:
 is_indicator_set_label(self, _("No active sensors"));
(I'm not C language guru, so, maybe I'm wrong, maybe problem is in other place ;))

Also I think, that untranslated Preferences Window title (string "Hardware Sensors Indicator Preferences") is because of line 108 in file /indicator-sensors/is-preferences-dialog.c line:
gtk_window_set_title(GTK_WINDOW(self), _(PACKAGE_NAME " Preferences"));

Maybe this line should be like this (I forgot C language many years ago, but you should understand my idea ;) ):
gtk_window_set_title(GTK_WINDOW(self), _(PACKAGE_NAME) + _(" Preferences"));