Hello Karl,
As I said in the previous message, the shortcuts are added to the scopes. And the shift+up shortcut is bound not to the task row, but to the task object. You can collapse and expand tasks, but the task row is just a DOM element.
The task row only shows some task rows, but it can be configured to show completely different information that is not related to the task at all.
If you enable the keyboard_navigation_cells config, you can use the shortcuts of the taskCell scope, but the taskRow is not available. If the config is disabled, it works vice versa: Keyboard Navigation Gantt Docs.
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