But there is no button which re-imports everything (why should it, this doesn't make sense).
The BUTTON is refresh.
The way I showed the OP to get to it will remove all transactions and re-query the mycelium servers for ALL the transactions on your addresses.
Try it.
With the refresh any new transactions it sees will come in.
With the reload you can actually see all your transactions disappear and come back.
This way if something is compromised with the local database it will fix it.
-Dave