Situation: You are editing a play > click save and continue and the thumbnail still shows the old diagram, when you go to print it is still the old diagram, but when you go back into edit the diagram the changes are reflected.
This is an easy fix! Your computer saves certain information like thumbnails and when editing plays, the old version of the play can sometimes be saved in your internet cache and thus the preview icons will not be updated. In order to fix this you simply need to refresh your browser cache.
Command + Shift + R (or click shift + refresh on your Google Chrome browser)
Ctrl + Shift + R (or click shift + refresh on your Google Chrome browser)