Quickpanel is a small popup desktop which supports widgets and desktop icons. When activated, it is shown at the center of screen.
Quickpanel can be run in KDE desktop and windows.
Use it in KDE Desktop:
$ zypper install python-qt5-devel python-kde5
$ git clone git@github.com:hgoldfish/quickpanel.git
$ cd quickpanel
$ python3 compile_files.py
$ python3 start_quickpanel.py
After quickpanel started, a system tray icon shown at the right bottom of your desktop. Click it or press Alt + `, shows the quickpanel.