Planning with fixed milestones

Hi all,
I've setup a project with a fixed milestone (=external deadline). I also setup a task which should be finished before this deadline. Hence I setup a end-start dependency between the task an the milestone. If the task takes longer such that it misses the deadline it looks like this after pressing the "planning" button.

The question: Is there a possiblity to get warning while planning (e.g. "dependency cannot be fullfilled")? Of ocurse I can maunally set a "validated end date" for the task to hit the milestone and the task becomes red if the date is is later than the validated one. However druing the initial planning I don't have this set. Thank you in advance for your help.

Best regards,

Udo Eisenbarth