You can create and manage quick filters for the timeline.Quick filters are saved JQL to filter out the Jira issues which don’t much the conditions. You can use filters in Schedule, Timeline and Gantt
All users who have access to the board can view and use the quick filters, on the toolbar click on Filter to enable or disable filters on the list
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To create
Create quick filter
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Project admin role is required for on project board and Jira admin role is required for on program board to create quick filter .
From board go to Board Settings → Quick Filters
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Click Add button to create a new filter
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Enter the filter name, the JQL and description.
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Scope if Global is checked the filter will be available for all boards in Jira instance
Default: if the filter is checked as default it will be always ON for all users on the Scheduler, Timeline and Gantt. Only admin can edit to make it not default.