More control over DockItem closing

[Brayconn]

I'm attempting to implement two features in my program:

1. An "Are you sure you want to close?" dialog when the user tries to close a tab with unsaved changes
2. A project settings menu that's toggleable by a checkbox

For the former, I need to be able to prevent a DockItem from closing when the user doesn't say "yes" to a dialog box.
For the latter, I need to be able to close the DockItem from code for when the user loads a different/creates a new project.

The closest I got to the first functionality was by registering a Button.ClickEvent handler and checking if((e.Source as Button).Name == "CloseButton"), but that method still can't prevent the DockItem from closing.
I didn't make any progress on closing the DockItem from code.

[npolyak]

sorry, I'll try to work on it in the near future.