added a trim check to prevent matching of white-spaces (which causes delays in large documents)

lib/util/match-highlighter.js

@@ -23,7 +23,7 @@
   function markDocument(cm, className, minChars) {
     clearMarks(cm);
 	minChars = (typeof minChars !== 'undefined' ? minChars : DEFAULT_MIN_CHARS);
-	if (cm.somethingSelected() && cm.getSelection().length >= minChars) {
+	if (cm.somethingSelected() && cm.getSelection().replace(/^\s+|\s+$/g, "").length >= minChars) {
 		var state = getMatchHighlightState(cm);
 		var query = cm.getSelection();
 		cm.operation(function() {