You can sort a list of issues several ways, including by issue creation date, milestone due date, etc. The available sorting options can change based on the context of the list. For sorting by issue priority, see Label Priority.
In group and project issue lists, it is also possible to order issues manually, similar to issue boards.
When you select Manual sorting, you can change the order by dragging and dropping the issues. The changed order will persist. Everyone who visits the same list will see the reordered list, with some exceptions.
Each issue is assigned a relative order value, representing its relative order with respect to the other issues in the list. When you drag-and-drop reorder an issue, its relative order value changes accordingly.
In addition, any time that issue appears in a manually sorted list,
the updated relative order value will be used for the ordering. This means that
A is drag-and-drop reordered to be above issue
B by any user in
a given list inside your GitLab instance, any time those two issues are subsequently
loaded in any list in the same instance (could be a different project issue list or a
different group issue list, for example), that ordering will be maintained.
This ordering also affects issue boards. Changing the order in an issue list changes the ordering in an issue board, and vice versa.