Support for views filters doesn't work as expected.

Issue Summary

I'm trying to make a view that sorts nodes in a random order but filters out any nodes with a weight less than 0 (i.e., anything in the negatives). That filter seems like it would be set using the Weight: Weight field and set to "is less than 0" but doesn't seem to filter anything at all. Changing the filter to "is greater than or equal to 0" just for testing returned an empty set when I have a couple dozen nodes with a weight in the teens.

Steps to reproduce:

1. Make a few nodes with weights below zero and a few with weights above zero
2. Make a new view to list then
3. Make the view sort by Global: Random
4. Add a filter with the field Weight: Weight and value 'is less than 0'
5. Observe that nodes with weights above zero are still displayed

Any ideas here?