Hot-Reload refers to the ‘Compile’ button on the editor toolbar. This will kick off a compile of your source, and reload the resulting binaries once complete, without restarting the editor. There are limitations to what you can do and still be able to hot reload- you cannot change the class memory layout for example. Hot reload can also be invoked from the ‘Modules’ window in the editor, something we used a LOT when developing editor tool modules.