Hi there,
You can disable the animation on that button or remove that button all together, read
my reply to What is the button called Online and Local logging?
A whole bunch of buttons can be disabled, a look through the preferences will show you the following:
The last one will make sure no promotional buttons are shown anywhere, not in contact list and not in chat window. As you can see even Messenger Plus! buttons themselves can be disabled should you wish to do so. As configurable as can be I'd say...
Missing anything in this overview? Feel free to ask.