Morning,
I have a JIRA project setup and I'm trying to remove the Create Sub Task button and instead use the inline subtask where you can easily and efficiently add sub-tasks using the plus/+ link which doesn't require the Create Sub-Task modal dialog to appear.
Here is a sample of the Sub-Tasks with the button that brings up the dialog (yuck).

I have a different JIRA instance where the sub-tasks can be created simply by clicking the plus button in the sub-tasks section:

So my question is how do I stop the dialogs from appearing and the inline sub-tasks additions to be enabled.
For reference the only field on the sub-task that is required is the Summary field.
I've searched high and wide however haven't found an appropriate answer as to how to enable the inline sub-task creation, the dialog is okay however it's so inefficient compared to the inline process.
Many thanks
Mark