Looking for a solution on a very small but somewhat annoying problem I have (guess i should be lucky to only have this kind of issues

)
The two small buttons on the indicator lever behind the wheel for the "Check" messages and "BC" for browsing through the board computer (time/temp, range, oil level etc) are rattling at certain speeds in my car... It started after fitting 20" wheels. The sound occurs on rougher tarmac and at certain speeds... I don't run very high pressure in my tires, the vibrations are only very subtly noticable when I hold my finger to the indicator lever itself. Currently I just hold my fingers on the buttons to make it quiet hehe.
Before I isolated the problem to these buttons I though it came from somewhere inside the fan/vent on the driver side or there around.
- Has anyone had the same problem and found a good workable solution?
Im thinking about putting a very small piece of cotton or something like that behind the buttons to see if that helps, but it might jam the button if I do too much and then it would be hard to get it out... Hence the question to get an answer from someone who has done some trail and error already

Like I said its a small issue, but with such a otherwise solid quality product as the M6 a sound like that can ruin some of the quality and solid feeling!
_