Zhongren,
Is your manifest.json set to know that your widget has a config.json?
"properties": {
"inPanel":true,
"hasLocale":true,
"hasStyle":true,
"hasConfig":true,
"hasUIFile":true,
"hasSettingPage":true,
"hasSettingUIFile":true,
"hasSettingLocale":true,
"hasSettingStyle":true,
"IsController":false,
"hasVersionManager": false
}
Is your config.json in the same folder as the Widget.js and named "config.json"?