Created attachment 1114 [details]
screenshot of active buy unresponsive Editor window
I'm still not exactly sure how to trigger it, but i happens to me often enough that this is a major problem. While editing multiple documents in the R.app editor, one or more become unresponsive to the cursor. I think that changes can still be made to the open documents, but the changes are not updated on the screen. I can still create a new document in the editor, and it acts like a document should, fully editable and responsive.
I've attached a screenshot of the problem. In the screenshot you can see the frontmost window is missing the icons and search bar that should be along the top of it, whereas the editor window to the bottom left remains fully functional and has its full complement of icons and search bar. If you look closely at the frontmost editor window ("Angelo Analysis") you can see multiple cursors at the same time.
I can't reproduce it but in GUI 1.40 we have a new editor so maybe it helps - please try the current R 2.13.0 alpha and advise whether the issue remains. Thanks, Simon.