Issue

When editing macros that use a modal window (or redirect to an external service), if multiple users edit the macro at the same time, changes are not updated live, and whoever saves the macro last will overwrite the changes of the previous person.

Steps to Reproduce

1. Run Confluence with Collaborative Editing enabled
2. Create a page and insert a macro such as Roadmap Planner.
3. Save the page
4. Edit the page, and click on the macro and select 'Edit'.
5. In another browser/private browsing window, log in with a different user and edit the same page/macro
6. In window #1, make a change to the macro, but do not click 'Insert'
7. In window #2, make a different change. Click 'Insert'
8. Back in window #1, click 'Insert'

At this point, only the change made in window #1 will be visible. The change in window #2 is gone.

Expected/Suggested Behavior

Update the changes in modal windows as well. If that cannot be done, then display a warning on the window that any changes made here could potentially be overwritten by someone else who is editing at the same time.