Fl_Panzoomer: Use FL_DAMAGE_USER1 to indicate that only the cursor needs to be redrawn.

FL/Fl_Panzoomer.H

@@ -69,7 +69,7 @@ public:
             _xpos = pos;
             _xsize = size;
 
-            redraw();
+            damage( FL_DAMAGE_USER1 );
 
             return pos;
         }
@@ -84,8 +84,7 @@ public:
             _ypos = pos;
             _ysize = size;
 
-
-            redraw();
+            damage( FL_DAMAGE_USER1 );
 
             return pos;
         }

src/Fl_Panzoomer.cxx

@@ -94,7 +94,8 @@ Fl_Panzoomer::draw ( void )
 void
 Fl_Panzoomer::draw ( int X, int Y, int W, int H )
 {
-    fl_draw_box( box(), X,Y,W,H,color());
+    if ( ! (damage() & FL_DAMAGE_USER1 ))
+        fl_draw_box( box(), X,Y,W,H,color());
 
     X += Fl::box_dx( box() );
     Y += Fl::box_dy( box() );