There is a bug that may be experienced especially by new users...
After adding your Location (➕) or Authorizing Things to ActionTiles, you may find some of them are not listed in the Location View and the "Add Thing Tile to Panel" dialog box.
This likely only occurs for Things selected from lists "3)" and/or "4)" on the SmartThings Authorize Things page. If the Things are shown in lists "1)" or "2)", you can workaround this bug by selecting them there instead.
Customer support service by UserEcho