Why has my Ctrl+Shift+U key for Unicode input stopped working?

Question

When I press Ctrl+Shift+u and type numbers, nothing happens. Holding down Control or Shift doesn't help, either.

I've tried running sudo dpkg-reconfigure keyboard-configuration, but that didn't solve the problem.

Solution 1

It hasn't stopped working in general, but the way it works may have led you to think that it has stopped working. When one types Ctrl+Shift+u an underscored letter u appears at the insertion point. This may lead a person (e.g., myself, at first) to think that he has entered an underscored letter u, whereas in fact the underscored letter u indicates the Unicode-entry mode has been activated. If one subsequently keys in a Unicode code point (i.e., the hexadecimal numeral for the character) and hits Enter then the unicode character will appear.

For example, Ctrl+Shift+u 2764Enter inserts a "heavy black heart" Unicode character.

Demonstration: ❤

Solution 2

The reason why entering Ctrl+Shift+u, Unicode hexadecimal number, Enter or Space stop working in Ubuntu 15.10+ is because input method is by default XIM instead of iBus (which is odd since XIM is obsolete and iBus already implement XIM protocol). By changing this they broke this useful shortcut.

To fix it, go to:

1. On GNOME Shell (17.10+, check with wmctrl -m):
   Settings → Region & Language → Manage Installed Languages → Language tab.

   ^{On Unity: System Settings... → Language Support.}

2. Keyboard input method system, change it to iBus.

3. Restart

Reference

• gnome - Understanding & setting up different input methods - Unix & Linux Stack Exchange

Comments

[EMBLEM]

The underlined U does not appear.

[MightyPork]

It stopped working for me too, must be some issue with GTK

[jdthood]

Just tested in gedit in Ubuntu 15.04. Worked fine.

[lisimba.gilkes]

It doesn't work for me on Ubuntu 14.04. It used to work on earlier versions of Ubuntu.

[somethis]

Confirmed for Ubuntu 18.08. --> ❤

[somethis]

It hasn't stopped working. Please check the solution from jdthood

[alife]

By the way, this answer bypasses the question entirely because the OP clearly knows how the ctrl+shift+u is supposed to work. It has stopped working for me since I upgraded to 20.

[alife]

@somethis, it has stopped working for many of us. The solution from jdthood isn't a solution: It's the way it was supposed to work, and I believe the OP knew this already with his question (he said "stopped working"). I can't get it to work in comments here, gmail, other edit fields, any editor, basically everywhere it used to work in 18.{mumble}.