I used the zoom function in kwin for a long time, but today suddenly it stopped working. When I push the buttons 'meta + =' the desktop is not magnified. It did not solve problem to change the shortcut to something like 'meta + z'.
What I did before seeing this issue are the followings.
I used yaourt in a tty session (I entered the session using Ctrl + Alt + F2). Here I reinstalled matplotlib, numpy, spicy using pip. Also I changed yaourt's build directory from /tmp to /home/$USER/tmp in order to install a large package(kicad-packages3d).
After playing in the tty session and rebooting I found my KDE desktop effect disappeared. Where could I start from in order to resolve this issue?