Credits to
Rob Camick: Relative Layout
https://tips4java.wordpress.com/2008/11/02/relative-layout/
Ernie Yu: Java Swing range slider
https://ernienotes.wordpress.com/2010/12/27/creating-a-java-swing-range-slider/
Alvin Alexander: Java: How to copy an image to the clipboard
https://alvinalexander.com/java/java-copy-image-to-clipboard-example
Mozilla Foundation: Font "Fira Sans Medium"
https://github.com/mozilla/Fira
Thanks to
the JAVA community, especially „stack overflow“
http://stackoverflow.com/questions/tagged/java
the authors of „Geany“
http://geany.org