How to reproduce it :

• Create a new folder in the documentary base : All buttons are displayed to the right side (ok the first one, cancel the second one)
• Display properties of a file and modify it : each button is on each side (cancel on the left, ok on the right)
• In the forum, on a discussion, add a new message : each button is on each side (ok on the left, cancel on the right) that is the reverse order the the previous case.
• Add a comment on a file of the documentary base : the cancel button does not have the same look like the others.