This macro hidden all objects not selected if you selected one object hidden the hidden object are displayed and all objects not selected are hidden

Macro_SelectVisible.FCMacro

import FreeCAD
# Macro_SelectVisible
__title__="Macro_SelectVisible"
__author__ = "Mario52"
__url__     = "http://www.freecadweb.org/index-fr.html"
__version__ = "00.02"
__date__    = "12/11/2015"

try:
    compt = 0
    for ShapeNameObj in FreeCAD.ActiveDocument.Objects:                                   # list alls objet for test if alls hidden
        if (FreeCADGui.ActiveDocument.getObject(ShapeNameObj.Name).Visibility == False) and (Gui.Selection.isSelected(ShapeNameObj) == False):
            compt += 1                                                                    # if hidden : compt += 1
            #print "False : ",ShapeNameObj.Name
    if compt == len(FreeCAD.ActiveDocument.Objects):                                      # if (compt = Alls objects hidden) then Visibility = True
        for ShapeNameObj in FreeCAD.ActiveDocument.Objects:
            FreeCADGui.ActiveDocument.getObject(ShapeNameObj.Name).Visibility = True      # Visibility = True
            #print "True  : ",ShapeNameObj.Name
        compt = 0
    else :
        for ShapeNameObj in FreeCAD.ActiveDocument.Objects:                               # hidde objects not selecteds
            if Gui.Selection.isSelected(ShapeNameObj) == False:
                FreeCADGui.ActiveDocument.getObject(ShapeNameObj.Name).Visibility = False # if objects is not selected then Visibility = False (Hidden)
                #print "False : ",ShapeNameObj.Name
            else:
                FreeCADGui.ActiveDocument.getObject(ShapeNameObj.Name).Visibility = True  # if objects are hidden and selected then Visibility = True and hidden alls objects visibles
                #print "True  : ",ShapeNameObj.Name
except Exception:
    None

This macro utility is intended for the use of the program FreeCAD http://www.freecadweb.org/
The icon for your toolbar, it is to place in your macros directory (in the same location of the macro)
rename in Macro_SelectVisible.png