An interesting problem with help presenting related

[Hammer Attila <hammera pickup hu>]

Hi,

Possible any package corrupted my Ubuntu 16.04 developer system or a 
package is not installed?
I newer seeing following issue with Orca screen reader for example, look 
the traceback error message:
If I press Orca modifier, press F1 key, I see following traceback error 
message the debug file:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/orca/input_event.py", line 660, 
in _consume
    self._consumer(self)
  File "/usr/lib/python3/dist-packages/orca/scripts/default.py", line 
923, in showHelp
    return orca.helpForOrca()
  File "/usr/lib/python3/dist-packages/orca/orca.py", line 462, in 
helpForOrca
    Gtk.get_current_event_time())
GLib.Error: g-io-error-quark: The gived place is not supported (15)

Orca using following code to present help content:
def helpForOrca(script=None, inputEvent=None, page=""):
    """Show Orca Help window (part of the GNOME Access Guide).

    Returns True to indicate the input event has been consumed.
    """
    orca_state.learnModeEnabled = False
    uri = "help:orca"
    if page:
        uri += "?%s" % page
    Gtk.show_uri(Gdk.Screen.get_default(),
                 uri,
                 Gtk.get_current_event_time())
    return True

This issue happening when I using Gnome Shell 3.18 version.
When I login back with Mate desktop environment, this issue not 
happening. With Ubuntu 16.04 awailable Mate version is gtk2 version.
If I trying running in Terminal the yelp help:orca command, the help 
topics wonderful displaying.
Other GTK3 applications the help topics not displaying too.
Anybody have any ydea what packages need me reinstalling to fix this issue?

Attila