Workflow "Diagram" window is really small and resizes after reload

Explanation

When you edit an workflow. the "Diagram" window will be really small. If you keep reloading the page (or performing any actions inside the "Workflow" section) the "Diagram" will keep resizing and growing after each reload.

Steps to reproduce

1. Log in to JIRA as an Administrator;
2. Type "gg" -> Workflows;
3. Click on "Edit" on an workflow of your choice;
4. The "Diagram" view will be really small;
5. If you reload the page (or perform any action inside the "Workflows" tab, such as switching to text and then back to diagram), the Diagram window will resize and grow;