middle mouse button

[AxeCrazy]

hai all,
just recently upgraded from yabbse to SMF.
What a major improvement 

Just a question.
using the misddle mousebutton gives the dynamic scroll indicator for scrolling through the webpage normally, but when clicking on  a signature in SMF it doesnt'
Also pageup/down ,home/end and Ctrl PageUP/Down are disabled.
Is this a setting, or....
It did work on my yabbse board.

Any ideas?