fcitx won't trigger IME on super+space

I'm on Ubuntu 14.04 LTS.

When I just finished installing the sougoupinyin IME with fcitx,Everything works fine.

I want to change the default hotkey combination of Trigger Input Method from L-CTRL + Space to Super + Space(Win + space) ,so that it make no difference from Microsoft Windows. The combination do changed to Super + Space , as shown from the Configration panel. However , the combination won't working.

Found the similar case here What is eating the Super+Space shortcut?

Since the desktop of ubuntu 14.04 is based on Unity ,the combination itself work fine when I use the ibus-based IME previously.

No idea about what to do. My keyboard layout is English-US.

Sorry for my poor English and formatting.

Thanks

As the comment mentions that in 18.04 and 18.10 the hotkey SUPER_SPACE does not work.

This can be fixed by unsetting the system hotkey in

System settings -> Devices -> Keyboard -> Switch to next input source

So I just had the same issue on Lubuntu 16.04, and have managed to fix it.

The Background

Basically when you change the Trigger Input Method variable in the Fcitx Configuration to Super+Space, the display shows it changing to SUPER_SPACE, but it actually gets set to SPACE (you can still type spaces by using Super+Space). The Fcitx configuration just changes the files in ~/.config/fcitx, so you can manually edit them. Look at these lines in ~/.config/fcitx/config, the TriggerKey has been set to SPACE not SUPER_SPACE:

# Trigger Input Method TriggerKey=SPACE

The Fix

• Manually change Line 3 of ~/.config/fcitx/config to TriggerKey=SUPER_SPACE and save.
• Reopen the Fcitx Configuration tool and apply without changing anything (updates your settings).

That should do it