I'm searching for a string and replacing it with nothing (ctrl+h), thus deleting all occurrences of a word in the document.
After the first click on the replace button, the replace string gets changed from empty, to the last string used for replace in the search and replace history.
This makes search and replace to remove a string, on a one by one basis throughout the document unusable.
Hope I'm reporting the bug on the right place. Thanks!