Edit metadata dialog: When clicking Next and Previous preserve the current tab of the edit comments widget. Fixes #1467129 [[Enhancement] HTML View in Metadata](https://bugs.launchpad.net/calibre/+bug/1467129)

src/calibre/gui2/comments_editor.py

@@ -730,6 +730,14 @@ class Editor(QWidget):  # {{{
                 self.editor.html = unicode(self.code_edit.toPlainText())
                 self.source_dirty = False
 
+    @dynamic_property
+    def tab(self):
+        def fget(self):
+            return 'code' if self.tabs.currentWidget() is self.code_edit else 'wyswyg'
+        def fset(self, val):
+            self.tabs.setCurrentWidget(self.code_edit if val == 'code' else self.wyswyg)
+        return property(fget=fget, fset=fset)
+
     def wyswyg_dirtied(self, *args):
         self.wyswyg_dirty = True
 

src/calibre/gui2/metadata/single.py

@@ -527,6 +527,7 @@ class MetadataSingleDialogBase(ResizableDialog):
             # break_cycles has already been called, don't know why this should
             # happen but a user reported it
             return True
+        self.comments_tab_at_apply = self.comments.tab
         for widget in self.basic_metadata_widgets:
             try:
                 if hasattr(widget, 'validate_for_commit'):
@@ -634,6 +635,8 @@ class MetadataSingleDialogBase(ResizableDialog):
         self.button_box.button(self.button_box.Ok).setDefault(True)
         self.button_box.button(self.button_box.Ok).setFocus(Qt.OtherFocusReason)
         self(self.db.id(self.row_list[self.current_row]))
+        if getattr(self, 'comments_tab_at_apply', None) == 'code':
+            self.comments.tab = 'code'
 
     def break_cycles(self):
         # Break any reference cycles that could prevent python