When running WPF and WinForms applications with async operations, I've run into a number of issues with event handling 'hanging' the UI thread in unexpected ways, where the UI hangs until the mouse is moved or a key is pressed. A lot of times these issues are associated with events that fire async code, and in this post I take closer look at one scenario that can cause these hang ups along with a workaround that has proven useful in a number of occasions for me.