MSP: Elapsed total float ignored - even when increasing threshold for critical tasks

No bugs.

1. Assuming you've left the project's "hours per day" at the default value of 8, then your critical slack threshold of 6 days is 6x8=48 hours.
2. On the two tasks selected, the Total Slack is 2.63 elapsed days x 24 hours per elapsed day = 63.12 hours.
3. Since 63.12 > 48, the two tasks are not Critical.
4. For these tasks to show as Critical, you would need to increase the critical threshold from 6 days to 8 days (i.e. 64 hours).

In this case, your true Critical Path might be difficult to discern without tracing the driving logic.

Good luck, tom 

Many thanks Tom! Brilliant :-)
I should have thought of that.

Henrik, glad you got it sorted.