Member show on Activate and Hide on deactivate from channel member list and at_mention

api/user.go

@@ -1510,6 +1510,8 @@ func UpdateActive(c *Context, user *model.User, active bool) *model.User {
 			RevokeAllSession(c, user.Id)
 		}
 
+		<-Srv.Store.Channel().ExtraUpdateByUser(user.Id, model.GetMillis())
+
 		ruser := result.Data.([2]*model.User)[0]
 		options := utils.Cfg.GetSanitizeOptions()
 		options["passwordupdate"] = false