Adding a folder to System Menu applet from KDE Task Panel

I found it frustrating not being able to add a folder to System Menu in KDE by just right-clicking or through the KDEMenu Editor. After some search, in fact the folders you see in this menu are located in /usr/share/apps/systemview/. To add one you’ll need to :
mkdir ~/.kde/share/apps/systemview/
And copy an existing .desktop, for example media.desktop
cp /usr/share/apps/systemview/media.desktop \
~/.kde/share/apps/systemview/somestuff.desktop
Then just edit the newly created somestuff.desktop by changing Name= and Path= to point on the folder.
On next login to your session it will appear!