TypeError: sequence item 0: expected string, Fragment found

[anonymous]

​trac:#13433

How to Reproduce

While doing a GET operation on /ticket/3, Trac issued an internal error.

(please provide additional details here)

1. After simplemultiproject turned on then I don't see the tickets and can't create ticket
2. Also related problem is

Error: Not Found
Unknown administration panel

..when clicking new created project

• I'm using plugin manager for admin, also not experimenting inside .ini

Request parameters:

{'id': u'3'}

User agent: #USER_AGENT#

System Information

System information not available

Enabled Plugins

Plugin information not available

Interface Customization

Interface customization information not available

Python Traceback

Traceback (most recent call last):
  File "venvp27/lib/python2.7/site-packages/trac/web/main.py", line 639, in dispatch_request
    dispatcher.dispatch(req)
  File "venvp27/lib/python2.7/site-packages/trac/web/main.py", line 271, in dispatch
    method=method)
  File "venvp27/lib/python2.7/site-packages/trac/web/chrome.py", line 1443, in render_template
    fragment, iterable, method)
  File "venvp27/lib/python2.7/site-packages/trac/web/chrome.py", line 1517, in _render_jinja_template
    data):
  File "venvp27/lib/python2.7/site-packages/trac/web/chrome.py", line 1930, in _check_for_stream_filters
    stream, data)
  File "venvp27/lib/python2.7/site-packages/workflow_actionbuttons/web_ui.py", line 39, in filter_stream
    buttons.append(manager.render_action_button(req, data['ticket'], action))
  File "venvp27/lib/python2.7/site-packages/workflow_actionbuttons/api.py", line 64, in render_action_button
    label, widgets, hints = self.render_action_control(req, ticket, action)
  File "venvp27/lib/python2.7/site-packages/workflow_actionbuttons/api.py", line 37, in render_action_control
    return first_label, tag(*widgets), (hints and '. '.join(hints) or '')
TypeError: sequence item 0: expected string, Fragment found