I have the same problem 🙊

Hm, as a data point I appear to have the buttons and they work so perhaps it's been fixed?

@TheTimeSavingCo is your End Date a function field? @Mgomezv can you recreate the `+ Add record` working like I can below?

- Created a new Gantt, selected an existing Start Date and let it create a new field for end date. The `+ Add record` is interactive. Clicking it shows the inline dialog.

- Created another new Gantt, selected an existing Start Date and used our existing End Date (function column). The `+ Add record` button is disabled (has the `disabled` attribute).

Nope, it's a date field!  I just tried converting it to a function field and it's now greyed out:

Wonderful, thanks so much @TheTimeSavingCo.

There it is! That's a bug. Or, at least, this is a broken expectation. A computed end date is the reasonable approach when defining task duration using a start date and duration. I'm hoping it's an oversight and not some implementation detail which is preventing addition of milestones and records.

Any chance we can get the attention of someone who can affect change?

Perhaps you could make use of the new Date Dependency feature?  https://support.airtable.com/docs/date-dependencies-in-airtable

It's basically the exact same functionality you're looking for, except with a Date field instead of a function field?

Hi @mseeley 

I did it, but for the first case only '+Add Record' are disable.
For second case '+Add record' and 'add Milestone' are disable.

In my case, i need that Gantt show a task list. All task have the same 'start date' and 'end date' (from linked record), but i need to include a milestone date for every different task.
How can i do it?

> In my case, i need that Gantt show a task list. All task have the same 'start date' and 'end date' (from linked record), but i need to include a milestone date for every different task.
> How can i do it?

Sorry @Mgomezv I'm unsure how you could accomplish that. Wishing you good luck!

@TheTimeSavingCo: Refactoring to use date dependencies resulted was a good suggestion, thanks!

Using a function for End Date allowed us to pad the duration by a fixed percentage (1.2 fwiw) uniformly across all records. I couldn't find a way to accomplish this using existing date dependency functionality.

But(!) using the date dependencies fixed the disabled `+ Add Record` and `+ Add Milestone` controls. It also fixed our inability to drag, drop, and resize records from the gantt view itself. It _also_ handles invalid precursor/successor dates. All of these were major inconveniences which the team is very happy to have resolved.

Thanks!