Descriptive Problem Summary:
Adding overlays to an area and then going out of range makes the overlays disappear until you re-enter that area

Numbered Steps to Reproduce Problem:
1. Add overlay to multiple areas
2. Run out of range of the area so you don't see it (plus a bit more)
3. Come back and your overlays will be gone from it until you re-enter

Code Snippet (if applicable) to Reproduce Problem:


Expected Results:
Moving in and out of viewing an area will retain it's overlays

Actual Results:
It does not, see video: https://youtu.be/OAZFgGBsDlk

Does the problem occur:
Every time? Or how often? Every time, multiple computers tested

When does the problem NOT occur?
things like area color are retained, seems just overlays and possibly underlays?

Did the problem NOT occur in any earlier versions? If so, what was the last version that worked? (Visit http://www.byond.com/download/build to download old versions for testing.)
Earliest version we can test is 1625 (and it does it then) up until 515.1642

Workarounds:
None found, vis_contents might work?