Key repetition misbehaves in Qt5 applications.

I am running a Plasma 5 desktop environment under Arch Linux. With the latest 
fcitx (4.2.8.5) and plasma-desktop (5.2.2) I have this issue:

In all Qt5 or KF 5 apps, e.g. Qt Designer, Kate, KWrite, key repetition will 
yield 2 chars each loop (not in IM candidate window but only in plain text 
mode, i.e. whichever goes directly to the underlying application (pure English, 
or entering backspaces...)

E.g. When pressing A and holding, the key sequence proceeds like this:
a -> aaa -> aaaaa -> aaaaaaa

Please don't not touch any configuration that is not mentioned in upper
document, developer can't guess your setup.
)

What steps will reproduce the problem?
1. Reduces the repetition rate to see clearly what is going on.
2. Open a Kate text editor.
3. Ensure that fcitx is running.
4. Press a key, say A, and hold.

What is the expected output? What do you see instead?
Expected: a -> aa -> aaa -> ...
Actual: a -> aaa -> aaaaa -> ...

What version of the product are you using? On what operating system?
Plasma desktop 5.2.2
Fcitx 4.2.8.5
Arch Linux

Please provide any additional information below.

Original issue reported on code.google.com by anohigis...@gmail.com on 3 Apr 2015 at 2:03

nooop3 / fcitx

Key repetition misbehaves in Qt5 applications. #748