webstorm I feel better after using the native Wechat developer tool, the inexplicable red line looks at obsessive-compulsive disorder. You can also try vscode

this seems to require the editor to install the plug-in support developed by Wechat. Go to the official website to see if there is anything related, and install it. If not, you might as well use Wechat's developer tools, or replace it with sublime text 3