Can't find an issue in the tracker for this, although I'm pretty sure it must have been reported. Anyway, the issue is easy to describe.
When importing XML files (e.g. glossary entries, questions, etc.) by drag&dropping them into the drag&drop area of the File picker, Internet Explorer will open that XML file in the current window, instead of considering it for import.
This is a serious drawback for the drag&drop feature, no?
Joseph