I had an issue with VSCode in UE4.25. I’ve created a component and added nothing to it, but every line was with red gear lines. Just check your .vscode->c_cpp_properties.json and if “defines” array will be empty than go https://gist.github.com/boocs/31e6c2e54815b7ba6246ee20315acf96#Step-9 and make this step
You put your remark in the wrong course!