[racket] Quarter-circle in upper right of Definitions window?

From: Prabhakar Ragde (plragde at uwaterloo.ca)
Date: Mon Sep 17 15:25:32 EDT 2012

Sorry if this is a dumb question. This small quarter-circle, with an 
arrow in it, appears from time to time, and then disappears. It contains 
some links to documentation. I cannot tell what is causing it to appear 
and what causes it to disappear...? Thanks. --PR

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