Hi,
Thank you for your interest in Essential Tools.
I am able to see the issue "ArgumentOutOfRangeException when selecting via initial letter" in 4.3. But this has been resolved in the version 5.1.0.51. Could you please upgrade to latest version? Our latest version 5.1.0.51 can be downloaded from the below link
http://www.syncfusion.com/downloads/latestversion/default.aspxFor Unlock Key:
If you hold a Syncfusion license with a valid subscription, you can obtain your key for this version by visiting the "Download the latest versions" section within Direct-Trac and clicking on the appropriate key icon. If you're currently evaluating our products or considering renewing an expired subscription, please contact our sales team (salessupport@syncfusion.com) for the key and further details.
Please let me know if you have any other questions.
Thanks,
Melba