dropping files to Kicad manager :
*.kicad_pro, *.pro -> open project;
gerber and job files -> open in Gerbview editor;
Eagle and Cadstar files -> open project.
dropping file to schematic editor -> append schematic;
dropping library file to Symbol editor -> add library;
dropping board file to PCB editor -> append board;
dropping library or footprint file to Footprint editor -> add library or import footprint;
dropping ZIP file or gerber files to Gerbview editor -> open files;
dropping sheet file to Drawing Sheet editor -> open sheet.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/11638
lulu731