Index: wp-includes/js/wplink.js
===================================================================
--- wp-includes/js/wplink.js	(revision 21920)
+++ wp-includes/js/wplink.js	(working copy)
@@ -40,6 +40,16 @@
 			});
 			$('#internal-toggle').click( wpLink.toggleInternalLinking );
 
+			// Prevent keypresses while form fields are focused from bubbling up to the form level,
+			// where the wpLink.keydown/keyup functions are hooked
+			$('#url-field,#link-title-field').bind( 'focus', function() {
+				inputs.dialog.off( 'keydown keyup' );
+			});
+			$('#url-field,#link-title-field').bind( 'blur', function() {
+				inputs.dialog.keydown( wpLink.keydown );
+				inputs.dialog.keyup( wpLink.keyup );
+			});
+
 			rivers.elements.bind('river-select', wpLink.updateFields );
 
 			inputs.search.keyup( wpLink.searchInternalLinks );