Problem with mouse & Prosel 8

[al190290@academ07.mty.itesm.mx (Alberto Roffe Illades)]

I have a not serious but annoying problem with the mouse in my Apple //e
(enhanced) and Prosel 8.
 
When I turn on the Apple it boots into Prosel 8 and a Prosel application
screen shows up with the first application highlighted. Then I start to move
the mouse to select the application I want, and the application gets
selected and executed as if I had pressed the mouse button!
 
At first I thought I clicked the button accidentaly but now I am pretty sure
I don't.
This only happens the first time after a cold boot (and not after an
OA-ctrl-Reset). Furthermore, This doesn't always happen but it does often.
 
I have a "bitMouse card" by Sequential Systems as the interface, and the
mouse brand name is "Besame" (weird name if you ask me :) ).
I bought both from Alltech Electronics sometime ago.
 
Any clues as to why this happens??
Thanks.
 
-Alberto Roffe
 (Mty, MEXICO)