Description of problem:
when i want to save a new document

Version-Release number of selected component:
cherrytree-0.29.4-1.fc19

Additional info:
reporter:       libreport-2.1.7
cmdline:        /usr/bin/python /usr/bin/cherrytree
executable:     /usr/bin/cherrytree
kernel:         3.11.1-200.fc19.x86_64
runlevel:       N 5
type:           Python
uid:            1000

Truncated backtrace:
ctdb.py:331:write_db_node:IntegrityError: column node_id is not unique

Traceback (most recent call last):
  File "/usr/share/cherrytree/modules/core.py", line 1153, in file_save
    and self.file_write(os.path.join(self.file_dir, self.file_name), first_write=False):
  File "/usr/share/cherrytree/modules/core.py", line 1244, in file_write
    self.file_write_low_level(filepath, xml_string, first_write)
  File "/usr/share/cherrytree/modules/core.py", line 1179, in file_write_low_level
    else: self.ctdb_handler.pending_data_write(self.db)
  File "/usr/share/cherrytree/modules/ctdb.py", line 64, in pending_data_write
    self.write_db_node(db, tree_iter, level, node_sequence, node_father_id, write_dict)
  File "/usr/share/cherrytree/modules/ctdb.py", line 331, in write_db_node
    db.execute('INSERT INTO children VALUES(?,?,?)', (node_id, node_father_id, sequence))
IntegrityError: column node_id is not unique

Local variables in innermost frame:
node_father_id: 95
sequence: 4
tag_property: 'link'
syntax: 'custom-colors'
pixbuf_table_codebox_vector: []
tag_found: False
txt: u'<?xml version="1.0" ?><node><rich_text>1. callback</rich_text></node>'
has_table: 0
is_ro: 0
dom_iter: <DOM Element: node at 0x29ea368>
curr_buffer: <gtk.TextBuffer object at 0x2103b90 (GtkTextBuffer at 0x29dd690)>
curr_iter: <GtkTextIter at 0x24b7a30>
sel_range: None
tree_iter: <GtkTreeIter at 0x26c7960>
tables_tuples: []
exporting: ''
images_tuples: []
write_dict: {'upd': False, 'buff': True, 'hier': True, 'child': False, 'prop': True}
is_richtxt: 1
tags: u''
db: <sqlite3.Connection object at 0x1f5ba28>
node_id: 67
has_codebox: 0
node_tuple: (67, u'BlueHeal', u'<?xml version="1.0" ?><node><rich_text>1. callback</rich_text></node>', 'custom-colors', u'', 0, 1, 0, 0, 0, 2)
end_iter: <GtkTextIter at 0x24b7f20>
name: u'BlueHeal'
level: 2
codeboxes_tuples: []
start_iter: <GtkTextIter at 0x24b7f70>
has_image: 0
self: <ctdb.CTDBHandler instance at 0x208af80>