Input key press event is fired twice (depending on input method ?)

Bug #1500912 reported by Jeremy Munsch on 2015-09-29
This bug affects 3 people
Affects Status Importance Assigned to Milestone

Bug Description


when pasting a hostname into synapse (eg. for ssh plugin) it is being pasted twice like:
clipboard: hostname
synapse: hostnamehostname

when hold shift key and selecting a hostname it opens 2 terminal windows for this host.

is there a configuration option for this or is it a bug?


EDIT: using GTK_IM_MODULE='' synapse solves the problem as a workaround

Jeremy Munsch (jeremy-munsch) wrote :

I just noticed that if you start synapse from cli the bug does not occur, howhever if you start using a graphical method your pastes will be doubled

nean (nean.and.i) wrote :

hmm, I can not confirm that.
If I start it via terminal the same issue occurs.
So whats different to your starting option?

Jeremy Munsch (jeremy-munsch) wrote :

Yeah right i just noticed i had an alias :
GTK_IM_MODULE='' synapse

This was because i had crash from synapse (it made crash my kde (plasma5.3 desktop).
Seems like it solves more problems.

I did had to use on plasma5.2.

I actually have echo $GTK_IM_MODULE => fcitx

So i check into the code: if you set GTK_IM_MODULE='' => paste is triggered once
in no => paste is triggered twice

Jeremy Munsch (jeremy-munsch) wrote :

I mean i did not have to use on plasma 5.2, cause synapse made no crash

Jeremy Munsch (jeremy-munsch) wrote :

Indeed key_press_event function is triggered twice so i do not know where is the bug, but sure there is.

Jeremy Munsch (jeremy-munsch) wrote :

If anyone is aware on how to debug synapse or vala programs don't hesitate, i'm real stranger to this programming language.

Jeremy Munsch (jeremy-munsch) wrote :

Well definitly a synapse bug.
    public override bool key_press_event (Gdk.EventKey event)
      message("keypress ");
      // this.controller.key_press_event (event);
      return false;
This is some recursive situation because if you comment the controller method the key press is fired once only.

Jeremy Munsch (jeremy-munsch) wrote :

I found the cause :

im_context.focus_in ();

On controller.vala line 55 the very specific instruction "im_context.focus_in ();"
 // Input Method Fix
if (this.view is Gtk.Window) //this has to be true, otherwise im_context will not work well
  Gtk.Window v = this.view as Gtk.Window;

  message ("Using %s input method.", im_context.get_context_id ());

  v.focus_in_event.connect (() => {
    im_context.reset ();
    im_context.focus_in ();
    return false;

  v.focus_out_event.connect (() => {
    im_context.focus_out ();
    return false;

I'm not sure what this is doing.

summary: - Paste in synapse doubles the paste
+ Input key press event is fired twice (depending on input method ?)
description: updated
description: updated
nean (nean.and.i) wrote :

seems it has something to do with the keyboard input method system which is in unity by default at "ibus"

there is a way to set it to "none" which might have the same effect as to set it via environment variable:

however, I need to find out more about input method, what it is all about and why it behave strange in synapse,...

Jeremy Munsch (jeremy-munsch) wrote :

@nean it is a synapse bug actually see above.

if you want to change you input method use : im-config to set it to none.

Like said, event is fired twice because of some code part i have tried to reach to original author but i'm waiting for an answer now.
I guess we could try to remove this code part.
If i have got any answer soon i'll make a merge request to fix this.

nean (nean.and.i) wrote :

thanks jeremy.

as tested in ubuntu 14.04.x
switching input method to "none" via im-config solves the problem.
(seems to be the same as to switch it via: system settings -> language support -> keyboard input method system )
However this might not be a solution for people who need "input method" set to "ibus" (korean, chinese keyboard etc,...)

Changed in synapse-project:
status: New → Triaged
importance: Undecided → Medium
milestone: none →
Changed in synapse-project:
milestone: → 0.3.0
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