Pat, I've tried everything I can think of, short of physically shaking my laptop.
However, I found a clue. I turned logging on (vis-a-vis the logging example) and I got the following repeating entry:
Dec 12, 2007 5:51:51 AM gov.nasa.worldwind.retrieve.HTTPRetrieve r doRead
FINE: Response code 200, Content length 0, Content type content type not returned, retrieving http://worldwind25.arc.nasa.gov/lsti...L=1&X=53&Y=110
Then I checked my cache (C:\ProgramData\WorldWindData\Earth\NASA LandSat I3\1\110) for 110_53.dds and ITS NOT THERE. This situation appears to preempt the display of the higher res tiles of the same map type.
Just for grins, I copied a random tile into the cache and renamed it 110_53.dds and the higher-res tiles were immediately displayed.
So, I suspect the new logic that requires the low-res imagery to be present may need to be reviewed as it creates a severe dependency on the availability and deliverability of all image tiles in the "pyramid".
Release 0.3.0 is not constrained with this requirement, thus the high-res tiles display even though a low-res tile is unavailable.