It seems it is a bug.
I did a test searching for jv16PT.exe, to be replaced by jv16PT.exe. (*) look below the screenshots for additional explanation.
It seems it does it correctly if the match is in the "Entry name."
However, if the match is in the "Data" (aka the "Value"), it does it incorrectly. It shows the "Entry name" in the before and after cells, and will not change anything for that match.
02-18-2009_11-25-44.jpg
02-18-2009_11-27-30.jpg
(*) Before doing the above test, I did a search for jv16PT.exe and actually did the replace to jv16PX.exe. The results window showed the same items as above.
Then I did a search for jv16PX.exe to change it back to jv16PT.exe. That results window did not show the c, c, a, or b lines.
Therefore, no change had occurred in those "Data" items.