Certain keyboard shortcuts are not working anymore, such as Ctrl-Shift-C for (un)commenting lines and Ctrl-Shift-M for the pipe.
Ctrl-L for clearing the console and Ctrl-Shift-N for a new file do work, though.
Until yesterday, these shortcuts worked fine.
I've deleted and re-installed RStudio, both the preview (1.3.1087) and the stable version (1.3.1073).
I also deleted the RStudio folder from the appdata folder, but the problem remains.
Check they haven't been remapped by looking in the edit keyboard shortcuts window.
Also, some shortcuts depend on what task you're presently working on.
I use Ctrl+Shift+D to duplicate lines constantly when I'm teaching or just coding on my own, so it's always frustrating to me when I'm working on a package and I want to make a copy of a line of code but I end up redoing my package documentation instead. So, verify you haven't changed anything else about how you're working in R too.
Thanks for your reply.
Another new installed program (AMD Radeon), which ran in the background, had taken over these keyboard shortcuts.
I uninstalled AMD and now they are working in R again