Terminator: shortcuts don't work after switching the keyboard layout

This also might be because you have german keyboard which physical layout is different than US or polish (for example the ? symbol on US software layout on nordic and German keyboards is typed by holding shift and pressing - symbol.

All regional keyboards have different layouts (with exception of modifier, function, cursor, system command and numeric keys)

Here is example of US keyboard layout

First, I should mention that this behavior is not only for "terminator" and not only for "Ubuntu"! I have seen shortcuts not working in Windows and even Mac when keyboard layout is changed! So, IMHO it is NOT a bug!

We have to better understand what a keyboard shortcut, e.g. Ctrl+F does! The Ctrl is called the modifier while F is called the non-modifier key.

When they are pushed in a software, they invoke a signal. Linux terminal uses the POSIX reliable and sometimes POSIX real-time signals. You can learn more about it by typing man 7 signal in your terminal. Terminator by defualt uses GNU style signals on linux.

Terminator is a terminal emulator which means it is a software developed that gives you the functionalities of a terminal and some additional features. Like many other softwares, you can configure how Terminator behaves by modifying its config file which usually can be found ~/.config/terminator/config.

Now, if you take a look at terminator help page for its config file you can see how this file is structured. There is a specific option, try_posix_regex which setting it to True makes the terminator to try POSIX style first. Try adding the following line under global_config:

try_posix_regex = True

Here is the explanation about the option:

try_posix_regexp (boolean)
          If  set  to  True, URL matching regexps will try to use POSIX style first, and fall
          back on GNU style on failure.  If you are on Linux but URL matches don't work,  try
          setting this to True.  If you are not on Linux, but you get VTE warnings on startup
          saying "Error compiling regular expression", set this  to  False  to  silence  them
          (they are otherwise harmless).  Default value: False on Linux, True otherwise.

I have not fully tested it, but it might resolve the issue. I am still investigating if holding a modifier key, e.g. Ctrl, somehow sends information about the keyboard layout with it or not. If it does, changing the layout will modify the signal send and therefore the terminal, terminator, or nay other software may not be able to interpret it correctly.