OK, here's a Mac problem related to the 4.4.3.2 IPTC Info zoom feature:
On a G5 2.3DP running OSX 10.4.6, the Control-Z option will not zoom the preview window (but clicking on it with the cursor does work, and with smooth, proper resolution).
On an Intel powered MacBook running 10.4.7, the Control-Z option DOES work as expected, as does the cursor click on the preview, which expands to smooth, proper resolution.
Checking the other keyboard shortcuts available for the IPTC Info window, and they all appear to work properly on the G5 (didn't try every single one). Just the preview zoom shortcut does not.