Opaque Move Size\n

When moving a window, fvwm2 can  draw just an
outline of the window while it is being moved. The other alternative
is to draw the window just as it normally appears while it is
being moved.  The opaque move size is a percentage of total screen area. 
If a window's area compared to the total screen size is greater than
this percentage, it will be moved transparantly. If it is less than this
percentage, it will be moved opaquely.  

Setting opaque move size to zero makes all windows move transparantly.
Setting it to 100 makes all windows move opaquely.