Can't use Gantt elements

[alex.l]

Hi,

It is not possible to change lag with drag-n-drop operation. You need to edit lags for dependencies with TaskEditor.
If you won't use lags but constraintDate, it will be possible to move task as you described. You can check it here https://bryntum.com/products/gantt/examples/advanced/

[sakina@mvclouds]

Currently, we are using the Lag option to get a gap of a few days between the end date of the predecessor and the start date of a child. Still, then we are not able to drag it back to any dates before the changed start date of the child, so is there a way which can allow us to drag and increase the gap between a child and its predecessor and all the following Childs in the dependency with the original child also shifts accordingly while allowing us to move the child date up even after save.

[arcady]

Task drag & resize features has a flag allowing to drag a predecessor and keep its successors intact but adjust dependency lags instead:
https://www.bryntum.com/products/gantt/docs/api/Gantt/feature/TaskDrag#config-pinSuccessors
https://www.bryntum.com/products/gantt/docs/api/Gantt/feature/TaskResize#config-pinSuccessors

Please check and let us know if that's what you need.

[sakina@mvclouds]

Is there a way without the use of lag to keep the difference between the end date of the predecessor and the start date of its child, as currently on click of save it's reverting the change and remove the gap, and makes the child's start date right after its predecessors end date?

[alex.l]

Hi sakina@mvclouds,

What exactly you did when you see reverting changes after save? What is a "child of the predecessor"?
Regarding to your question, there might be 3 options for having gap between 2 tasks with dependency end-to-start between:

1. last task is manuallyScheduled, so it won't react on any changes of successor.
   https://bryntum.com/products/gantt/docs/guide/engine/gantt_events_scheduling#manually-scheduled-events
   https://bryntum.com/products/gantt/docs/api/Gantt/model/TaskModel#field-manuallyScheduled
2. last task has constraints, so, for example, it won't be able to start before some date.
   https://bryntum.com/products/gantt/docs/guide/engine/gantt_events_scheduling#event-constraint-effect-on-the-scheduling
3. dependency has a lag specified.
   https://bryntum.com/products/gantt/docs/guide/engine/gantt_events_scheduling#propagating-changes-through-event-dependencies