I guess this fixes issue 3747

Change-Id: I35fc3860776796b5d925a9bd176ec3e7a0ca89ca
Reviewed-on: http://gerrit.dmdirc.com/872
Reviewed-by: Gregory Holmes <greg@dmdirc.com>
Automatic-Compile: Gregory Holmes <greg@dmdirc.com>

src/com/dmdirc/parser/irc/IRCParser.java

@@ -1321,7 +1321,7 @@ public class IRCParser implements SecureParser, Runnable {
 
         final StringBuilder builder = new StringBuilder(chanPrefix.size());
 
-        for (Character prefix : chanPrefix) {
+        for (Character prefix : new LinkedList<Character>(chanPrefix)) {
             builder.append(prefix);
         }