possibility to ''lock'' a date in gant/schedule view

there are often some date that are fixed like cabinet and subcontractor and ‘‘supposed’’ delivery . as those are sometime almost impossible or very hard to move without having an issue with all the schedule.

I would like to have an option to ‘‘lock’’ certain date even if those are linked to other task as predecessor or else.

in the view you’ll have a lock inco beside it and everytime you made a change that would have moved this date. you received a pop-up notifing you that this would change this locked date to X instead of Z. this option would allow template to be easier to adapt to every job .