Has anyone seen a bug where you are using the WPF AutoCompleteBox control and while the drop-down is displayed you drag the window and the drop-down stays put while the entire window moves and now the drop-down is completely disconnected from the input field?
Does anyone know which event I could turn the drop-down off in this case? Or how to fix this?

Sounds like the Popup control strikes again. I don’t use AutoCompleteBox but I think it has an IsDropDownOpened property. You could set that to false when the window is moved. Maybe not the most elegant solution but it should workaround your issue.