How do I get iTunes to show my iPhone when connected via WiFi?

When starting iTunes 11.1.2 my iPhone 4S (iOS 7.0.3) turns up (in the upper right corner), then disappears after a few seconds. If I manage to click the button the iPhone window appears and then disappears. No problem connecting via USB cable.

The strange thing is that the invisible iPhone responds to iTunes diagnostics, see extract of report (in danish with some translation):

" ...
Info om tilsluttede enheder: (connected units)
CA-iPhone, iPhone 4S afvikler firmware version 7.0.3 (uses iOS 7.0.3)
Serienummer: DNQxxx (serial no.)
**** Test af enhedssynkronisering **** (testing sync of unit)
Synkroniseringstest udført. (sync test completed)
"

Regards
Claus A.

Answers