The clipboard stops working when I copy non-text onto the Clipboard.

Scenario 1:

- I run the test gtk clipboard app.
- I run Microsoft Word.
- I copy text, the app sees that text.
- I create an image (with Ctrl+Print Screen) and paste it - this fails!
- I stop running the app.
- I then go back to word, and try pasting again - this works!

Scenario 2:

- I run Microsoft Word.
- I run the test gtk clipboard app.
- I copy text (in the document), the app sees that text.
- I copy an image (already in the document), the app does not see the
change (because i await text only).
- I then go to copy the SAME text and the app fails to notice the clipboard
change. 

I wrote a Windows test program to access the clipboard directly (using
their APIs) and all seems fine in these scenarios.