Descriptive Problem Summary:
When you shift filters by pixels in Y axis with render_source mouse opacity behaves like if you shift filter in the other way

Numbered Steps to Reproduce Problem:
You need to have objects on your screen outside the map, so their screen_loc would look, for example, like this "SOUTH-1, WEST"
Create a FOV-like filter that overlays only a part of the screen

Does the problem occur:
Every time? Or how often?
Every time
In other games?
Yes
In other user accounts?
Yes
On other computers?
Yes

When does the problem NOT occur?
When you dont have any objects outside the game map

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.)
513.1510