if you open mutiple files already having IPTC data for IPTC editing, the first file displays blank fields on all tabs. At first I thought, the data really disappeared, but after playing with it, filling and re-filling, I discovered it's only a display problem (a very confusing one

Steps to reproduce:
1. Edit IPTC data on some JPG files filling some fields on several tabs.
2. Select some of these files (at least 2), click Ctrl+I (or right click -> Edit IPTC/XMP).
3. Look at the data in the first file (and don't panic), all fields seem to be empty.

4. Don't change anything! Navigate to the second file, then back to the first, (and take a deep sigh,) the data is back, the fields are filled.
