Connected task move

There are 3 tasks connected as shown in the image. When moving one of these tasks, is there a way to move the connected task of the moving task together?

Hello Seungmin,
You can do that if you select all connected tasks and turn on the multiselect extension:
You can see how it works in the following sample:

There is no built-in way to simultaneously move the linked tasks, but you can implement that by using Gantt API and Javascript.

For example, you can add the eachSuccessor function to get the linked tasks:
By using it, you can update their dates and repaint the changes.

Here is an example of how it can be implemented: