I'm reasonably well versed in all tabs except scheduler; now trying to migrate over.    Something I don't understand about the scheduler is the "Repeat until" completion constraint.   Intuitively, I would think that if I set up a sequence and then set the "repeat until" completion constraint, the job would run the sequence repetitively until the time is up (and abort if the sequence isn't completely finished with the Nth iteration?).   However, I've tried to set up a series of time constrained observations like this (giving about 5 minutes break in between stop/start times), but when I schedule multiple targets this way, I almost always see a message that says:
    "Warning: job '<target>' has fixed startup time X unachievable due to the completion time of it's previous sibling, marking invalid".  
So, what am I doing wrong?   What I'm trying for is simple time constrained, back-to-back target observations (e.g. 2 hours on target1, then 2 hours on target 2, etc.).   How is this best setup in the scheduler without triggering the Invalid status warnings ?    In the example screen shot (simulator), Polaris is scheduled twice, start time/end times appear ok, but the #2 scheduled item is changed invalid as soon as the next schedule item is added....   ???
Thanks for any advice.