Horrible horrible decision to remove the sync button. What were you guys thinking? You try to save the pixels in our monitors?
People have been learned to be paranoid about losing unsaved changes, so a manual save or sync -button gives the peace of mind, even if it was all placebo and nothing would actually happen. But in your case there really was need, as there was significant delay on the automatic sync and it's possible that you quickly need to close the laptop - and changes would not be synced.
Please try to use your brain more in future, when getting these "bright ideas" to "improve" things, which are already working.