Ensured that slider works with the new implementation

* Now the shift press is dynamic during the dragging and the grab is properly disengaged after letting go of the mouse, regardless if this happens over the object or outside it.

pd/src/g_slider.c

@@ -373,6 +373,20 @@ static void slider_motion(t_slider *x, t_floatarg dx, t_floatarg dy)
     }
 }
 
+
+// we use this exclusively to dynamically capture shift presses when
+// dragging the slider
+static void slider_list(t_my_numbox *x, t_symbol *s, int ac, t_atom *av)
+{
+    if (ac == 2 && IS_A_FLOAT(av,0) && IS_A_SYMBOL(av,1))
+    {
+        if (!strcmp("Shift", av[1].a_w.w_symbol->s_name))
+        {
+            x->x_gui.x_finemoved = (int)av[0].a_w.w_float;
+        }
+    }
+}
+
 static void slider_click(t_slider *x, t_floatarg xpos, t_floatarg ypos,
     t_floatarg shift, t_floatarg ctrl, t_floatarg alt)
 {
@@ -392,19 +406,27 @@ static void slider_click(t_slider *x, t_floatarg xpos, t_floatarg ypos,
     x->x_is_last_float=0; // does anyone know how this works with !steady && rcv==snd ?
     slider_bang(x);
     glist_grab(x->x_gui.x_glist, &x->x_gui.x_obj.te_g,
-        (t_glistmotionfn)slider_motion, 0, 0, xpos, ypos, 0);
+        (t_glistmotionfn)slider_motion, 0, slider_list, xpos, ypos, 0);
 }
 
 static int slider_newclick(t_gobj *z, struct _glist *glist,
     int xpix, int ypix, int shift, int alt, int dbl, int doit)
 {
     t_slider *x = (t_slider *)z;
+    //post("slider_newclick dbl=%d doit=%d grabbed=%d", \
+        dbl, doit, x->x_gui.x_glist->gl_editor->e_grab ? 1 : 0);
+
     if(doit)
     {
         slider_click(x, (t_floatarg)xpix, (t_floatarg)ypix, (t_floatarg)shift,
             0, (t_floatarg)alt);
         x->x_gui.x_finemoved = !!shift;
     }
+    else if (dbl == -1)
+    {
+        // genuine mouseup
+        glist_grab(x->x_gui.x_glist, 0, 0, 0, 0, 0, 0, 0);
+    }
     return (1);
 }