I´m using a common type keyboard that is configured as US international with dead keys. It worked normally on my desktop computer (before it died) and it worked normally when I used to ssh into my Raspberry Pi. The problem is with the ´/¨ key. It has to be pressed twice to display anything and it´s then the wrong character. This is the character that is displayed ´ and this is the correct character '. As you can see they are not the same.
Just be certain, I tried this with the Python IDE and I get an invalid character error. I Have another keyboard (a tiny difficult to use wireless keyboard) that does display the ' character correctly but not the shifted ' which should be a ¨ character. In this case it displays the @ character. if I then press the shifted 2 character then ¨ is displayed.
So, the keyboards are not at fault and the error only shows up when the keyboards are directly connected to the Raspberry Pi. As an experiment, I have selected a few different keyboards from the Raspberry Pi configuration menu but the problem persists. Can anyone offer a suggestion? A lengthy Internet search has not provided an answer.