Keyboard shortcuts

Keyboard shortcuts in Firefox: see the following link:
https://support.mozilla.com/en-US/kb/keyboard-shortcuts-perform-firefox-...
See also: Firefox.

List of shortcuts, and shortcut conflicts

Shortcuts can be set at many different levels: the desktop manager (KDE Plasma, etc), the application, the current window, etc.

Sometimes, conflicts may arise between the different levels. Some shortcuts that suppose to work at the application level no longer do because they are handled and caught at a higher level.

Unfortunately, it can be very hard to figure out which shortcuts are already in use somewhere, and what is catching a given shortcut that no longer works as expected for the user.

There lacks a tool to list all keyboard shortcuts currently available, and where such shortcuts are configured.

Ctrl

If a keyboard shortcut involving the Ctrl key stops working, try in another shell session if it prints properly.
For example, if Ctrl + W stops working as expected, try opening a new terminal (outside the current desktop session, e.g in TTY1) and type:
Ctrl + V then Ctrl + W: it should print the ^W.

Discoverability

A user should be able to easily find the shortcut for a command he may use frequently.
Often, in a application menu entry, the shortcut is written in parenthesis next to the action to be performed.
Sometimes, however, a user may not be aware of existing keyboard shortcuts that may facilitate his workflow.

One user very often opened many browser tabs in the background by doing: right-click -> open link in new tab only to discover much later, by chance, that a simple middle button click was having the same effect and was much easier to perform. The problem arises from the fact that such keyboard shortcuts may not always be easily discovered by the user.

KDE Plasma

KDE Plasma catches all shortcuts defined within the system. All shortcut that it does not catch are passed to the application. The problem is that withing KDE plasma, there does not appear to be a central location where all defined shortcuts are listed. Each widget on the plasma desktop can have its own shortcut defined.

Also, if an application is not receiving the proper shortcut, check within:
~/.config/plasma-org.kde.plasma.desktop-appletsrc
and see if it is defined there in, like for example: