Test project here: http://www.quiktech.org/sight_bug.zip

Descriptive Problem Summary:
There is differing behavior between Dream seeker and the Webclient when sight and see_invisible are used together. This is important as just setting see_invisible without setting sight won't trigger it.

In the above demo clicking on the blue dot should cause the blue dot to disappear and the purple turfs to appear black(meaning you can't see them). This is the current behavior using Dream Seeker.

However, in the webclient the blue dot does disappear, but the purple turfs remain purple giving the impression that you can still see them.