Re: rotate, scale tools dissapearing in viewports

sounds weird but here I give you some possible solutions:
When the manipulator is gray, it means the parameters are locked.  Check in the
channel box if the scale x y z are gray.  If they are, right click in the name
of the parameter an choose unlock parameter.  But if they are not, sometimes
happens that the top, front, left cameras goes in front of the geometry so you
never see the manipulators because they are behind the camera.  In general you
never notice it because this cameras are hidden by default.  So select the 3
cameras in the outliner and press shift + h to unhide them and pull them back if
they are inside or in front the geometry.  Don't forget to set correctly the far
and near clipping plane in your cameras.