the work around is to edit component json file manually. 
admin GUI can display, but not able to edit.
$ cat footer.json
{
"collectionName": "components_global_footers",
"info": {
"displayName": "Footer",
"icon": "arrow-down",
"description": ""
},
"options": {},
"attributes": {
"footerColumns": {
"type": "component",
"repeatable": true,
"component": "shared.footer-columns"
},
"socialNetworks": {
"type": "component",
"repeatable": true,
"component": "shared.social-network"
},
"button": {
"type": "component",
"repeatable": false,
"component": "shared.button"
},
"label": {
"type": "string"
}
}
}