The order of the contradictory BB-codes implementation is wrong

1. Go to "New Answer" screen
2. Add any text, select it and click "Right" BB-Code button
3. Then select the whole new text and click "Left" BB-Code button
4. Press "Preview" button
AR: BB-Code used later doesn't work (the text is still oriented to the right)
ER: The last used BB-Code has the priority (the text should be oriented on center)

The problem only happens with the contradictory BB-Codes (such as different Font sizes, different Margin sizes, different Colors and different text orientation - Left, Center, Right BB-Codes buttons).
The same problem occurs on "New Topic" and "New PM" screens.