Past work indicates that attended visual verbal stimuli are automatically encoded together with their spatial location but not vice versa. A new study by Elsley and Parmentier confirms this observation and demonstrates that the automatic binding of the "where" to the "what" remains stable during at least 15 seconds (the longest interval used in the study).
Reference: Elsley, J. V., & Parmentier, F. B. R. (in press). The asymmetry and temporal dynamics of incidental letter-location bindings in working memory. The Quarterly Journal of Experimental Psychology.