The source of the old, free notecase version is here. libgtksourceview2.0-0 is needed.
After downloading I tried to run make and got an error.
===> Linking bin/notecase /usr/bin/ld: ./bin/eggtrayicon.o: undefined reference to symbol 'XFlush' //usr/lib/i386-linux-gnu/libX11.so.6: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status Makefile:319: die Regel für Ziel „bin/notecase“ scheiterte make: *** [bin/notecase] Fehler 1
After running make "LDFLAGS=-lX11" the binary was linked.