Also I've finally found a friend willing to test it for me. He runs 16.04LTS/gcin2.8.4/firefox69.01, and there's no issue at all. Not sure how much this helps though as mine was also working before. Sorry I can't find other Ubuntu/firefox user friends who speak the language and use gcin. Thank.
Crtl+Space behaves normally on Chrome.
Also I've finally found a friend willing to test it for me. He runs 16.04LTS/ gcin2.8. 4/firefox69. 01, and there's no issue at all. Not sure how much this helps though as mine was also working before. Sorry I can't find other Ubuntu/firefox user friends who speak the language and use gcin. Thank.