X Rotation using MouseBehaviorJ3D

Hi

I've hooked up three sliders bars to a control the x,y,z rotation of a 
ProjectionControlJ3D object.  I've been using the MouseBehaviorJ3D 
unmake_matrix method to get the current matrix.  I then make changes to the 
matrix based on my slider bars, and then call the MouseBehaviorJ3D 
static_make_matrix method to build my new matrix.  I've noticed when I do 
this that both the Y and Z rotation values range from -180 to 180 degrees, 
but the X rotation ranges from 0 to 90 then down to -90 and back to 0 
degrees.  Is there a reason that  the X rotation uses a different range than 
the Y and Z rotations?  Is there a way to get all three rotations using the 
same range without writing some kind of hack?

Thanks,
Jason