Attaching picture. I feel current design is wrong. Does not look good stretched. Especially when all other design options has this button centered (makes me thing this is more a bug).
Only stretched ones are: "Right Floating Box" and "Left Floating Box"
P. S. If you combine this plugin with facebook chat plugin - on mobile device it goes on top of each other and since "OK" button is not centered - it is completely lost under fb chat plygin