You are viewing a plain text version of this content. The canonical link for it is here.
Posted to user@guacamole.apache.org by Nick Couchman <ni...@gmail.com> on 2022/06/16 20:07:24 UTC
Ctrl-Shift-Alt Woes
Hello, everyone,
I've posted a couple of times out this in various places, but I'm seeing
some really odd behavior after version 1.4.0 for Ctrl-Shift-Alt sequences.
I've used the Keyboard API tester, and I'm seeing a few oddities, there, as
well. I will try to describe them as best I can, though it's a little hard
to describe...
First, I see an issue where, during the Ctrl-Shift-Alt keypress sequence,
the Alt key-down doesn't get sent until another key is released. Here's the
sequence that I press:
* Press Control
* Press Shift
* Press Alt
* Release Control
* Release Shift
* Release Alt
Here is how the actual timing works out on the Keyboard API Test page:
* Press Control
guacamole keydown 0xffe3 Left control
* Press Shift
guacamole keydown 0xffe1 Left shift
* Press Alt
* Release Control
guacamole keyup 0xffe3 Left control
guacamole keydown 0xffe9 Left alt
* Release Shift
guacamole keyup 0xffe1 Left shift
guacamole keyup 0xffe9 Left alt
* Release Alt
Two things jump out, here:
* The "Alt" keydown doesn't get sent until the "Control" key is release.
* Both the "Shift" and "Alt" keyup events occur as soon as "Shift" is
released - while "Alt" is still pressed.
The second interesting one is this:
* Press Control
* Press Shift
* Press Alt
* Release Alt
* Release Shift
* Release Control
This results in the following sequence:
* Press Control
guacamole keydown 0xffe3 Left control
* Press Shift
guacamole keydown 0xffe1 Left shift
* Press Alt
* Release Alt
guacamole keydown 0xffe9 Left alt
guacamole keydown 0xffe7 Left meta
guacamole keyup 0xffe7 Left meta
guacamole keyup 0xffe9 Left alt
* Release Shift
guacamole keyup 0xffe1 Left shift
* Release Control
guacamole keyup 0xffe3 Left control
The items of note, here, are that:
* The Alt keydown is not sent until Alt is actually released.
* The Meta keydown is sent along with the Alt keydown, which is completely
unintended.
The practical implications of this are that the hidden Guacamole menu gets
stuck or the web page things that a key is still pressed, so that, after
the first time that I open the menu, if I simply press Ctrl-Shift, the menu
pops in or pops out, presumably because there is some "confusion" about the
state of the keys.
It's entirely possible that my window manager (Xfce) is throwing some
challenges into the mix, but this only stopped working for me after
updating from 1.3.0 to 1.4.0, with the same window manager, so _something_
in that version change seems to have broken things for me. Any ideas?
Re: Ctrl-Shift-Alt Woes
Posted by Nick Couchman <vn...@apache.org>.
On Thu, Jun 16, 2022 at 4:18 PM Nick Couchman <vn...@apache.org> wrote:
> Just another note, here - the issue does not seem to be related to the
> Control key - it's something about the Shift key. If I do the key sequence:
> * Press Shift
> * Press Alt
> * Release Alt
> * Release Shift
>
> I see:
> * Press Shift
> guacamole keydown 0xffe1 Left shift
> * Press Alt
> * Release Alt
> guacamole keydown 0xffe9 Left alt
> guacamole keydown 0xffe7 Left meta
> guacamole keyup 0xffe7 Left meta
> guacamole keyup 0xffe9 Left alt
> * Release Shift
> guacamole keyup 0xffe1 Left shift
>
>
Well, I have managed to figure out at least part of what's going on here.
Apparently Linux tends to map Shift + Alt -> Meta. This can be un-done,
but, by default, if you are holding Shift while you press Alt, you get
Meta. This can be seen with "xev":
KeyPress event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1150678547, (59,133), root:(930,609),
state 0x0, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: False
KeyPress event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1150679124, (59,133), root:(930,609),
state 0x1, keycode 64 (keysym 0xffe7, Meta_L), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: False
KeyRelease event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1150679335, (59,133), root:(930,609),
state 0x9, keycode 64 (keysym 0xffe7, Meta_L), same_screen YES,
XLookupString gives 0 bytes:
XFilterEvent returns: False
KeyRelease event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1150679398, (59,133), root:(930,609),
state 0x1, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
XLookupString gives 0 bytes:
XFilterEvent returns: False
There are a couple of interesting things to note, here, that may still be
buggy with how Guacamole handles it:
* xev does not show any delay in pressing the "Alt" key the way that the
Guacamole Keyboard Test page does (Alt keydown was not shown until Alt was
released).
* xev only shows the Meta key event, it does not show the Alt key event,
whereas Guacamole shows both Alt and Meta.
* Order of the key presses matters - if you press Ctrl + Alt + Shift,
things behave as expected - no Meta keypress, no funny hidden menu
behavior, etc. If you press Ctrl + Shift + Alt, you get funny results.
Based on a hint from a forum post (
https://askubuntu.com/questions/567731/why-is-shift-alt-being-mapped-to-meta),
I use xmodmap to remove the Shift + Alt mapping to Meta, and, with xev this
seems to work:
KeyPress event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1151683225, (165,-13), root:(1036,463),
state 0x0, keycode 37 (keysym 0xffe3, Control_L), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: False
KeyPress event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1151683371, (165,-13), root:(1036,463),
state 0x4, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: False
KeyPress event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1151683570, (165,-13), root:(1036,463),
state 0x5, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: False
KeyRelease event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1151683720, (165,-13), root:(1036,463),
state 0xd, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
XLookupString gives 0 bytes:
XFilterEvent returns: False
KeyRelease event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1151684195, (165,-13), root:(1036,463),
state 0x5, keycode 50 (keysym 0xffe1, Shift_L), same_screen YES,
XLookupString gives 0 bytes:
XFilterEvent returns: False
KeyRelease event, serial 37, synthetic NO, window 0x4c00001,
root 0x79b, subw 0x0, time 1151684327, (165,-13), root:(1036,463),
state 0x4, keycode 37 (keysym 0xffe3, Control_L), same_screen YES,
XLookupString gives 0 bytes:
XFilterEvent returns: False
However, to this point, this has not impacted how the Guacamole Keyboard
API interprets the keys - I still see the Meta key trigger when pressing
Ctrl + Shift + Alt. Not sure if I just need to restart Chrome, or if this
is truly a bug??
-Nick
>
Re: Ctrl-Shift-Alt Woes
Posted by Nick Couchman <vn...@apache.org>.
On Thu, Jun 16, 2022 at 4:07 PM Nick Couchman <ni...@gmail.com>
wrote:
> Hello, everyone,
> I've posted a couple of times out this in various places, but I'm seeing
> some really odd behavior after version 1.4.0 for Ctrl-Shift-Alt sequences.
> I've used the Keyboard API tester, and I'm seeing a few oddities, there, as
> well. I will try to describe them as best I can, though it's a little hard
> to describe...
>
> First, I see an issue where, during the Ctrl-Shift-Alt keypress sequence,
> the Alt key-down doesn't get sent until another key is released. Here's the
> sequence that I press:
>
> * Press Control
> * Press Shift
> * Press Alt
> * Release Control
> * Release Shift
> * Release Alt
>
> Here is how the actual timing works out on the Keyboard API Test page:
> * Press Control
> guacamole keydown 0xffe3 Left control
> * Press Shift
> guacamole keydown 0xffe1 Left shift
> * Press Alt
> * Release Control
> guacamole keyup 0xffe3 Left control
> guacamole keydown 0xffe9 Left alt
> * Release Shift
> guacamole keyup 0xffe1 Left shift
> guacamole keyup 0xffe9 Left alt
> * Release Alt
>
> Two things jump out, here:
> * The "Alt" keydown doesn't get sent until the "Control" key is release.
> * Both the "Shift" and "Alt" keyup events occur as soon as "Shift" is
> released - while "Alt" is still pressed.
>
> The second interesting one is this:
> * Press Control
> * Press Shift
> * Press Alt
> * Release Alt
> * Release Shift
> * Release Control
>
> This results in the following sequence:
> * Press Control
> guacamole keydown 0xffe3 Left control
> * Press Shift
> guacamole keydown 0xffe1 Left shift
> * Press Alt
> * Release Alt
> guacamole keydown 0xffe9 Left alt
> guacamole keydown 0xffe7 Left meta
> guacamole keyup 0xffe7 Left meta
> guacamole keyup 0xffe9 Left alt
> * Release Shift
> guacamole keyup 0xffe1 Left shift
> * Release Control
> guacamole keyup 0xffe3 Left control
>
> The items of note, here, are that:
> * The Alt keydown is not sent until Alt is actually released.
> * The Meta keydown is sent along with the Alt keydown, which is completely
> unintended.
>
>
Just another note, here - the issue does not seem to be related to the
Control key - it's something about the Shift key. If I do the key sequence:
* Press Shift
* Press Alt
* Release Alt
* Release Shift
I see:
* Press Shift
guacamole keydown 0xffe1 Left shift
* Press Alt
* Release Alt
guacamole keydown 0xffe9 Left alt
guacamole keydown 0xffe7 Left meta
guacamole keyup 0xffe7 Left meta
guacamole keyup 0xffe9 Left alt
* Release Shift
guacamole keyup 0xffe1 Left shift
Additionally, if I use the Alt key on its own, or with other keys (letters,
for example), it works fine. And, if I press, Alt, first, and then Shift,
the keydown/keyup also works as expected. It is something about the Shift
-> Alt sequence.
-Nick
>