If I view a diff, and then right click in the gray bar, Annotate is always grayed out.
If I go to commit files, and double click one of them to get a diff view, and then right click in the gray bar, Annotate is not grayed out. If I then click on Annotate, it'll say computing ... in the bottom status bar, and then that message goes away and nothing happens. If I then right click on the gray bar again, Annotate is grayed out.
Annotate works fine in standard views, aside from diffs.
This is using IDEA 10.5, with SVN.