I have very much difficulty to set criteria on edit search page

let's say I try to select editor=jesus2099 for instance :

1. I click the select, then click the Editor options
2. Some fields appear on the right but the select instantly re-opens
then sometimes :
3a. I click the new text field to fill it up, then the select gets blank (if I submit I get an empty WHERE clause error "SELECT edit.* FROM edit WHERE ()")
or
3b. I click the text appeared field, then the select doesn't get blank but after search submit, this line disappeared and found no edits either

This is like this for every selects on the edit search page.

(sometimes I manage to set the search criteriums but, without lying, it is a bit seldom)

I do use Opera 11.50 (1074) on Windows XP.