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Since WBS Gantt-Chart does not support this specific feature regarding hiding done/completed issues like a quick filter - a functionality that is already reported as a suggestion at the Public Tracker project, on WGCPT-76: suggestion on our Productboard Quick filters - here is a quick and simple alternative to hide completed issues on Gantt-chart by creating and saving a new filter for the project, where all the issues' status should be selected, except for the Done Status. That would be the quickest way to see all the issues except the completed ones, and no updates on the issues would be necessary.
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