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

[Ulrich Sibiller]

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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