Code review comment for lp:~diegosarmentero/unity8/processing-signal

I think we should instead replace the button with

ProgressBar {
  indeterminate: true
}

This way we don't need the weird "Purchasing…" string, nor we have a button which is not really a button, in the UI. And then the bottom activity indicator is meant to convey that there's communication between the dash and the scope, so the whole page isn't ready, which isn't the case here.