holy cow, this is weird.
all i did IN 1 QUERY was change the display format of a date field from MM/dd/yy to dd/MM/yy
and it rendered Filtering on that column 100% useless.
(I changed it locally in the grid)
Its a TIMESTAMP field, with its Display format = MM/dd/yy hh:mm
And I have overridden in the Grid cause I don't need to see the Time portion, but thats for debugging if we need to see exactly when something happened.
Once I changed the display format, I could not even use the Date Picker. No combination of typing in date values made the filter work - in all cases it filtered to NO Records Found.
Didn't believe it would be so difficult. Gotta get back to work. Good luck.