In Opera 9.64 on Windows XP Pro, entry of tags for a new question is very difficult.
Enter the first tag, select it in the AJAX popup.
Enter a second tag, select it in the AJAX popup.
Then, notice that sometimes the first tag has been replaced with the second tag. Alterntively often the second tag has been inserted into the middle of the first tag.
For example, on this question I want to add the tags: opera tagging bug
Following the above approach I actually get:
bug tagging bug
This is very frustrating and makes sensible tagging almost impossible. Please fix ASAP.
Upgrade to Opera 10. Initial testing on StackOverflow and SuperUser indicate that entering tags now works correctly in Opera 10.