disappearing document in views

The data in my (linked) documents do not show up in vertical or three pane views, although if I open a new window, they show up with no problem. This has happened a couple of times. It seems to occur after doing a couple of searches and having a few document panes open as I write up a rich-text document in yet another pane. All this works beautifully. I don’t know if it’s connected, but the ruler is grayed out in the offending document, so all my notes and found documents have a ruler at the top.
I can just continue to open a new window, but it is a bit of a nuisance. Any ideas about what causes this and what the fix might be?

That’s a very rare issue and has been reported few times during the last year. However, we’ve been unable so far to reproduce this and therefore it’s hard to debug this. It might be a bug of DT or of the OS.

If you’re able to reproduce this, then any additional information would be really appreciated. But luckily it’s a harmless issue - closing the window and opening a new one (or restarting the app) fixes the problem.