User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36 Steps to reproduce: If you have an folder open with a lot of emails and you are start typing in the quick search box (ctrl + shift + k) characters show up asynchronious and everything hangs. (content search is activated) It would be better if the search would run in an separate thread so the input would show ip in realtime. Actual results: Multiple press on key because input is not showing up -> after a couple of seconds the wrong input (same key multiple times). So you always have to correct your input -> gets very annoying. Expected results: input would show ip in realtime in the search field

The field you are referring to is quick search. This is covered in bug 1284753, which has lots of detail