The work it can take sometime to get your accent characters working properly… The French language is somewhat cursed – a terrible way to view things – but typing accents can be infuriating on a standard English(American layout) keyboard. That’s where the compose key comes in. A key on the keyboard can be assigned to be the compose key so that you can type things like ‘à’, or ‘ç’ or ‘É’ and any other possible combinations of letters and accents your heart desires.
Upon recently switching to Fedora 26 with KDE Plasma from Linux Mint 18.2 with KDE Plasma, I discovered that assigning the the compose key was a bit more difficult. For one thing, pressing the left-Win (left-Meta) key was actually launching the Application launcher
This just wouldn’t do.
First I right-clicked on the little Fedora icon and selected ‘Application Launcher Settings’. Under Keyboard shortcuts I cleared it out to ‘None’.
Next I opened System Settings and navigated to Input Devices>Keyboard>Advanced.
From here, I expanded ‘Key to choose the 3rd level’ and selected ‘Right Win’ to perform that function. Then, under ‘Position of Compose key’ I picked ‘Left Win’.
This now allows me to create a ‘é’ for instance by pressing the Left Win key, then the ‘e’ followed by the quote key (between colon/semi-colon and Enter).