[REACT] GANTT: how to make dependencies "push" back previous tasks

[clovisapp]

Hi Bryntum team,

We'd like to change the standard behavior between dependencies, especially to push back the tasks.

Example:

• task 1 has dependency with task 2
• task 2 is moved in the past
• WRONG behavior for us: task1 is not moved, and task 2 is "aligned" with task 1 end date
• EXPECTED havior: task 1 should be moved in the past if task 2 start date overlaps task 1 end date

How to provide this behavior ?

Thanks a lot for your help !

[ghulam.ghous]

Hi @clovisapp,

That is by design. Because you are using auto scheduling with forward scheduling. In a forward scheduled project (default), the Gantt engine schedules tasks as soon as possible. So upon moving a task backward, the next task in hierarchy, gets rescheduled and as there is a slot available before the current startDate, it changes its date and position. You can read about it here:

https://bryntum.com/products/gantt/docs/guide/engine/gantt_events_scheduling#automatic-event-scheduling
https://bryntum.com/products/gantt/docs/guide/engine/gantt_events_scheduling#forward-scheduled-project

And in order to get rid of this behaviour, you can simply set the task to be manually scheduled. See here:
https://bryntum.com/products/gantt/docs/api/Gantt/model/TaskModel#field-manuallyScheduled

Regards,
Ghous

[clovisapp]

@ghulam

If "manuallyScheduled" is set to "true" for tasks and subtasks, then the dependencies are not working which is not right (the Task 1 is not pushed in the past by Task 2).

We'd just like to have normal gantt behavior with Bryntum. Do you want some examples of Asana, Notion, Microsoft Projects Gantts ?

Thanks a lot for your help !

[ghulam.ghous]

For manuallyScheduled tasks:

When set to true, the startDate of the task will not be changed by any of its incoming dependencies or constraints.

The above is the documentation for manually scheduled tasks.

I will check with the person who implemented Engine and will see that how we can avoid this behaviour somehow (seems pretty unlikely)

[clovisapp]

@ghulam yes i know it, it tested it directly under dev.

I just need a solution:

• to make bryntum dependencies work like normal gantt softwares
• to disable all the other "bryntum magic" calculations (what is called automatic scheduling)

What i understand is that there's no solution for that right ? Appart of catching a task drag change, then performing ourself the dates changes on the other impacted tasks, right ?

[clovisapp]

Sounds like it would be a very good idea to choose between all the rules you put inside "automatic scheduling"

[clovisapp]

I've made a comparison here: https://clovisteam.notion.site/Standard-Gantt-behaviors-comparison-02c8f8b1d78345bab928670aae89a318?pvs=4

I don't see this "move back" behavior in all generic and standard gantt softwares

[mats]

Do you mind adding a quick video showing MS Project behavior to the mix as well as that's the "golden standard" for project management software?

[clovisapp]

@mats

I can't test it as i have a mac, and MS Project Online is full of bugs.

On microsoft project online:

• the "push back" just simply removes the dependendy to allow the moving of the task 2 (task 1 is not moved)
• the "push forward and move back" has the same behavior as Notion and Asana

I also tested Zoho Project, they have the behaviors hard to understand but that can be close to Bryntum's one.

Anyway, i highly think all of that should be highly configurable with Bryntum, and not included with "Basic" implementation.

[mats]

Agree, this could be valuable for anyone coming over to our camp from the Notion/Asana universe. Ticket opened here: https://github.com/bryntum/support/issues/8898

If have any additional feature suggestions, please let us know - we very much value your feedback!