[X2Go-User] Configure x2go-client to not forward specific key combinations?

[Jonah Benton]

Ok, thank you, it looks like more guidance will be very welcome; in looking
through the source tree and docs I can guess at a link where there needs to
be a tool referenced in the NX_CLIENT environment variable, but starting
x2goclient as:

$ which nxdialog
/usr/bin/nxdialog
$ NX_CLIENT=/usr/bin/nxdialog x2goclient

does not yield different autograb behavior. Will continue to experiment but
any additional details will be great, thanks again.

Jonah


On Fri, Jul 10, 2020 at 11:54 AM Ulrich Sibiller <uli42 at gmx.de> wrote:

> Hmm, interesting. Ah, yeah, I know what the problem really is. NXCLIENT
> variable is wrong. I will provide a longer answer later.
>
> Uli
>
> Jonah Benton <jonah at jonah.com> schrieb am Fr., 10. Juli 2020, 16:42:
>
>> Thank you- hmm, it looks like using the autograb key combo (c-a-g) causes
>> the entire window to disappear. In the session.log below, this shows up as
>> a request to suspend the session. Is that expected behavior? I'm using the
>> Fedora 32 XFCE spin, with Fedora's packaging of x2go, for both local and
>> remote environments.
>>
>> Info: using keystrokes file '/etc/x2go/keystrokes.cfg'
>> Info: ignoring unknown keystroke action 'debug_tree'.
>> Info: ignoring unknown keystroke action 'regions_on_screen'.
>> Info: ignoring unknown keystroke action 'test_input'.
>> Info: ignoring unknown keystroke action 'deactivate_input_devices_grab'.
>> Currently known keystrokes:
>>   close_session         : Ctrl+Alt+t
>>   switch_all_screens    : Ctrl+Alt+f
>>   minimize              : Ctrl+Alt+m
>>   resize                : Ctrl+Alt+r
>>   defer                 : Ctrl+Alt+e
>>   ignore                : Ctrl+Alt+BackSpace
>>   force_synchronization : Ctrl+Alt+j
>>   fullscreen            : Ctrl+Shift+Alt+f
>>   autograb              : Ctrl+Alt+g
>>   viewport_move_left    : Ctrl+Shift+Alt+Left
>>   viewport_move_right   : Ctrl+Alt+Right
>> Session: Session resumed at 'Fri Jul 10 10:32:35 2020'.
>> Info: Screen [0] resized to geometry [2560x1576] fullscreen [0].
>> cat: /proc/183021/environ: Permission denied
>> Session: Suspending session at 'Fri Jul 10 10:32:54 2020'.
>> Info: Waiting the cleanup timeout to complete.
>> Session: Session suspended at 'Fri Jul 10 10:32:55 2020'.
>>
>>
>>
>> On Fri, Jul 10, 2020 at 8:52 AM Ulrich Sibiller <uli42 at gmx.de> wrote:
>>
>>>
>>>
>>> On Fri, Jul 10, 2020 at 2:41 PM Jonah Benton <jonah at jonah.com> wrote:
>>> >
>>> > Thank you Uli, follow up below-
>>> >
>>> > On Fri, Jul 10, 2020, 2:52 AM Ulrich Sibiller <uli42 at gmx.de> wrote:
>>> >>
>>> >> On Thu, Jul 9, 2020 at 10:54 PM Jonah Benton <jonah at jonah.com> wrote:
>>> >> >
>>> >> > Hi folks,
>>> >> >
>>> >> > I'm interested in using x2go to:
>>> >> >
>>> >> > * connect into several individual accounts/machines at the same time
>>> >> > * use each remote machine desktop in full screen mode
>>> >> > * switch between remote full screen desktops using a specific key
>>> combination, which would therefore not be sent to the remote
>>> >> >
>>> >> > Is this possible?
>>> >> >
>>> >> > In my initial perusal of man pages and testing I don't see a way to
>>> do what seems to me to be the (probably wrong) solution- instruct the
>>> x2go-client (in either launch remote desktop mode, or desktop screen
>>> sharing mode) to not capture a specific key combination (like
>>> control-alt-right arrow and control-alt-left arrow) so that the parent
>>> desktop can handle them (e.g. switch between parent-side virtual desktops).
>>> >>
>>> >> Well, switching between application windows is a task of your local
>>> >> window manager or, more precisely, its task switching app. The reason
>>> >> you cannot do this in fullscreen sessions is that a session running in
>>> >> fullscreen mode will grab the X server to get ALL keys. That means no
>>> >> other application will get notified of keypresses. The hotkeys
>>> >> ("keystrokes") will be processed by the nxagent and will not reach the
>>> >> session. All others will be forwarded to the session. We could add
>>> >> another keystroke, something like "passthrough" or similar to pass
>>> >> that keystroke to your local X server. But even then I doubt that
>>> >> would work at all because usually grabbing prevents such things from
>>> >> happening. The only other options was to explicitly disable the grab
>>> >> in fullscreen mode which will probably lead to making your local
>>> >> session unusable because a window that is covered by the x2go
>>> >> fullscreen needs some interaction but cannot be activated or similar.
>>> >>
>>> >> A more pragmatic approach: do not run in fullscreen but use maximized
>>> >> windows instead. Then your local window manager/task switcher will
>>> >> happily fullfill your request to switch to another x2go session.
>>> >>
>>> >> Uli
>>> >
>>> >
>>> >
>>> > The explanation is very helpful and it along with running some
>>> experiments has clarified the mental model and convinced me of the futility
>>> of my imagined approach. Events are pushed to the client window without
>>> grab, but are pulled by the window with grab, acted on or not, and
>>> discarded.
>>> >
>>> > So re using maximized windows- the grab behavior allows for key
>>> combinations like alt-tab, or copy paste, that are present both locally and
>>> remotely to be only processed remotely.
>>> >
>>> > In the absence of grab, can I still achieve the ergonomics of working
>>> natively in the remote environment, as with alt-tab? For keys, would I need
>>> to bind each needed key combination in the remote environment to a key
>>> combination unused in the local environment? Or maybe only alt-tab and
>>> shift-alt-tab?
>>> >
>>> > Or is there an "ungrab" but leave full screen, then "regrab" when
>>> necessary?
>>>
>>> Hmm, some time I ago we implemented a feature called "autograb". In
>>> default setup you can can enable/disable it using ctrl-alt-g. In that mode
>>> the grab gets activated when the x2go window gets focus. That means when
>>> the window is active alt-tab and other combinations will be grabbed by x2go
>>> while they will be interpreted by the local session when the x2go window is
>>> not active. This allows you to use alt-tab in an x2go session without the
>>> local session interfering. So I suggest you experiment with a mixture of
>>> alt-tab and ctrl-alt-g. If you see room for improvement here please let us
>>> know.
>>>
>>> Uli
>>>
>>
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