Of course! Right after just posting those test results I encountered a bug with debugging case statements.
| str char | str := '1234' readStream. char := str next. char ifNil: [ Error signal ]. char caseOf: { [$4] -> ['four']. [$3] -> ['three' asUppercase]. [$2] -> ['two']. [$1] -> ['one' asUppercase]. } otherwise: [ 'No' ]
The issue is that it highlights "signal" of "Error signal".
It's also interesting, but somewhat understandable, that it doesn't highlight the blocks with no message sends in them.
Best, Chris