Clipboard gets cleared when application quits

Under Linux, when a Qt application copies something to the clipboard (e.g. via QClipboard::setMimeData() or QClipboard::setText()), it remains in the clipboard only as long as the application is running. As soon as the application quits, the clipboard is cleared.

This issue seems to be specific to Linux. Under Windows, the text remains in the clipboard after the application has quit.

Attached is a minimal test program that demonstrates the issue:

1) qmake && make

2) start the test program, you'll see a message box. Don't close it!

3) run an editor

4) hit "Paste" - you'll see the text "Hello, World!" being inserted

5) close the message box of the test program

6) return to the editor

7) hit "Paste" again - you'll see that nothing is inserted anymore