Bucket deletion not yet complete / rebalance failure

If a large bucket is deleted from the Couchbase Server UI it can take longer than the timeout allowed for the UI element. And a warning message comes up "Bucket deletion not yet complete, but will continue" (see screenshot 1).

While this is happening in the background the user is prevented from performing a rebalance (see screenshot 2).

2 Issues,

The UI doesn't show there's an ongoing task. It should be displayed on the top right like a rebalance or a compaction.
If the remove of the bucket is node by node, the UI should indicate which node is currently removing the bucket.

The UI should grey out the rebalance button during the bucket delete as the buckets aren't ready and the rebalance will fail while this task is ongoing.