1. Set Estimated time as a totalable column in Administration\Settings\Issue tracking
2. Display a list of issues: the estimated time is shown at the top and for each group if the list is grouped.
3. Unroll the Options, uncheck Estimated time (and any other column for totals if there are), Apply Result: the Estimated time total is still shown.

In fact, it is not possible to completely remove totals if one or more column is set in the global settings.

For us, it is an issue,

1. Because we want to have default totalable columns, as this is not saved in Custom queries (for the moment, maybe it will come in the future?)
2. We want to produce some issue lists in PDF without showing time information, so without having totals shown.

A possible fix would be to add a hidden field in the issue filter form, and set it to indicate global settings should not apply when the user manually changed all totals to unchecked (attached patch, based on 3.2.0 code). This is not very elegant, but it works.