Synergy-core: Shift key randomly gets stuck down

Created on 28 Mar 2015  路  11Comments  路  Source: symless/synergy-core

Confer https://github.com/synergy/synergy/issues/9, randomly I'll be typing along and my letters will come out as caps, without caps lock being enabled. Even pressing the shift keys on the server keyboard doesn't help, I have to reach over and press the right-hand shift key on the client keyboard to unstick. Pressing the left one does not help.

Of course, moving to the server or another client does not cause the shift key to be stuck in this case.

The shift key is never stuck down while using the client's local keyboard.

bug

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I can confirm this problem. My environment looks like this:

Server is a Kubuntu 64bit system (problem occurs with 14.04, 14.10 and 15.04).

Client is Windows 7 32bit.

The problem only occurs on the client. The Shift key seems to be pressed permanently on the client (randomly). Sometimes additionally the Strg key is stuck. Symtoms are:

  • When clicking in a list (file list in windows explorer, multiselect box), multiple items get selected
  • When clicking on a program in the taskbar, a new instance is opened, when the Strg Key is also stuck the new instance will be run as Administrator.

Pressing the Strg / Shift keys on the keyboard of the client makes them unstuck.

Update: Sometimes I need to press the right Strg / Shift buttons, sometimes the left ones.

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I have a similar problem. I have a Dell Inspiron Duo running Ubuntu 12.10 as a client and a Dell Inspiron One running Windows 7 Home Premium as the server. When the client connects I move the cursor to the client and am able to login. After moving the cursor off of the client screen to the server screen and then back to the client screen the caps lock is stuck on for the client even though it is not pressed on the keyboard. Using either of the shift keys on the client had no effect. The left shift key on the server also didn鈥檛 have any impact. However, once you use the right shift key on the server everything is magically fixed. Both keyboards work correctly and moving the cursor from machine to machine does not bring the incorrect keyboard function back. Once the client is re-booted then the problem comes back again but it is cleared up with the right shift key.

I can confirm this problem. My environment looks like this:

Server is a Kubuntu 64bit system (problem occurs with 14.04, 14.10 and 15.04).

Client is Windows 7 32bit.

The problem only occurs on the client. The Shift key seems to be pressed permanently on the client (randomly). Sometimes additionally the Strg key is stuck. Symtoms are:

  • When clicking in a list (file list in windows explorer, multiselect box), multiple items get selected
  • When clicking on a program in the taskbar, a new instance is opened, when the Strg Key is also stuck the new instance will be run as Administrator.

Pressing the Strg / Shift keys on the keyboard of the client makes them unstuck.

Update: Sometimes I need to press the right Strg / Shift buttons, sometimes the left ones.

See also these related issues:

  • Modifier/meta keys get stuck down #9 (closed)
  • Left mouse button gets stuck in right click mode on OS X client #3823
  • Ctrl or shift keys randomly simulated while in IE #3194
  • Command key stuck (Mac client, Windows server) #4057
  • Arrow keys and ctrl+arrow causes screen rotation on Windows #4449
  • Modifier state becomes out of sync on screen lock #4519
  • Modifier keys often stuck down on Mac client #4564 (merged)
  • Sticky Keys - Linux #4816

A fix was just merged specifically for Mac clients (Modifier keys often stuck down on Mac client #4564), but this problem is cross-platform with possibly-different root causes on each and probably still needs more attention.

Thank you for the hint!

I think I'm facing the exact same issue that is described in #4519. I also use a combination Strg + Shift + L to lock my Windows Screen and after I login both modifier keys are stuck.

Server: Synergy 1.7.6 on Windows 7 (64-bit)
Client: Synergy 1.7.6 on Mac OS El Capitan (10.11.4)

Since upgrading the server from 1.7.5 to 1.7.6 whenever the client connects, the keybinding I set on my Logitech mouse (a thumb-button set to "CTRL-W"; set through SetPoint Control Center 6.67.83) stops working correctly. (Other bindings, such as doubleclick, work fine; double-checked that it's not the button itself.)
The command "CTRL-W" doesn't work at all鈥攕ometimes, though, the CTRL-key gets stuck (with all the obnoxious side-effects that creates).

Current workaround: Fire up Synergy on the server, stop it, then restart it. Everything works fine afterwards.
The error arises again when disconnecting and then reconnecting the client.

Issue was not present with 1.7.5 as a server.

(Currently figuring out minimal reproduction steps and how to generate relevant log-files.)

I still experience the issue on 1.8.8 (both client and server). Has there been a fix merged at some point on a subsequent version?

EDIT (2019-03-14): I'm on GNU/Linux. Specifically Debian testing (buster). I also have clients and servers on Archlinux.

So what's the plan about this issue?

With newer Linux kernels (5.4/5.5) this is worse than ever.

Open source forks of Synergy have fixed this issue. Feels a bit like the money spent on a license was useless if bugs that are 5+ years old are still around.

Said f-it and switched to barrier. No issues with modifier keys for days.

@Smurf Hi, Synergy is still open source. Could you link to the issue/commit that fixes this in other forks? We can easily merge it in.

I just bought this software 2 days ago and just found this issue because it literally happens all the time. Impossible to work with! will ask for a refund!

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