Issues dragging scores with MuseScore Connect panel enabled

nightly f8d5642, Win8 64-bit. Same problem under Win7 32-bit.

Steps to show the issues:

1. Start MS nightly
2. Close any open score
3. Enable the MuseScore Connect panel
4. Drag a score so it passes over the MuseScore Connect panel and drop it on the empty score area
5. The score will not open and the Connect panel will go from "Connect with the community" to "Could not connect"
6. Turn off the Connect panel and dragging will work

7. Now re-enable the Connect panel and click on "Retry" in the Connect panel
8. Windows 8 will pop up a window saying "no apps are installed to open this type of link (qrc)", but the Connect panel will connect

See http://musescore.org/en/node/21088 for the original report.