LucasArts inventory scrolling

[Ytterbium]

I'm trying to get my inventory window to scroll, but whenever I click a scroll button, the cursor mode is rendered unchangable and I have to quit the game. Oh, and it doesn't work. Here's a diagram:

Displayed area is between *'s
*1 2 3 4 5* 6

I'm trying to change it to...
1 *2 3 4 5 6*

I use...

Code: ags

  else if (button == 5) {
      // scroll down
      game.top_inv_item += 1;
    }
    else if (button == 4){
      // scroll up
      game.top_inv_item -= 1;
    }

in the inventory script, but this code causes the problem to occur. Help!

[Scummbuddy]

This is what my code looks like.  Maybe it can give you some ideas?

Code: ags

      if ((button == 10) & (game.top_inv_item < game.num_inv_items - 7))
         game.top_inv_item = game.top_inv_item + 4;
      if ((button == 9) & (game.top_inv_item > 0))
         game.top_inv_item = game.top_inv_item - 4;