Hi Derek,
Thanks for your feedback on this issue. This is a known shortcoming in the EditControl and we have an open bug report defect 119 on this. I have updated this report with your inputs and we will try our very best to address this issue at the earliest. You could track the progress of this bug fix at this link below :
Defect #119 - EditControl application freezes on pressing Ctrl+End keys
We appreciate your patience, and thanks for your interest in Syncfusion products.
Regards,
Guru Patwal
Syncfusion, Inc.