Here are the problems:
* On our live-system (4.2.2), our employees are not able to open up Office files via *Edit in Office* or *Edit Document* with Internet Explorer 9. The file is opened, but as Read-Only. The system is configured to use HTTPS.
* On a freshly installed test-system (4.2.12), the normal left click didn't do anything at all with IE 9. Using the middle mouse button although, I was able to open up the files correctly and without the Read-Only flag.
We first used XP with Office 2003 ... everything worked just smoothly. After updating to Win 7, some of the PCs kept Office 2003 ... and everything worked as well. It only affects the Win 7 + Office 2010 machines.
This is critical for us, since we still have a lot of .doc, .xls and so on which are not yet migrated to native Wiki content.