Critical path affected by constraints

[Oberneder Mike]

I've read that a Critical Path (CP) can be affected by constraints. I've also read that "constraints" are stronger than dependencies (the "logic" sequence of the tasks). Lets say Task A and Task B are on the CP. Task A has a Finish-to-Start (FS) relationship to Task B. Task A ends on Wed, and Task B has a Start No Earlier Than (SNET) constraint to the following Monday. Therefore there would be elapsed days between the Wed and following Monday, and therefore there is slack. The CP is therefore broken, so that Task A will no longer show up on the CP. Now for my question, that I'm hoping someone can answer! Same situation as above with Task A and Task B. But lets say Task A ends on a Friday. Task B still has the constraint to SNET the following Monday. I didn't use dates for simplicity, but to be more precise, lets say Task A has a Finsh date of Friday 14 March 2014, and Task B has a SNET date of Monday 17 March 2014. In this case, the FS logic would give a Start date to Task B of 17 March 2014 which is the same date as its constrained date (SNET) also 17 March 2014. Therefore the total slack is zero. Since constraints are stronger than dependencies, will this constraint break the critical path so that Task A is no longer on the CP? There are no elapsed days, and the total slack is zero. But there is still a SNET constraint on Task B, which happens to coincide with the Task B start date dictated by the schedule "logic".

Thanks in advance for your help!