Jorge:

All too often I seem to find an item on a shelf moved all the way to the left on a shelf. Seems to happen when I try to launch a application too quickly and do a small drag by accident. Once that happens, I still find it very difficult to get the icon back into the position I want. Dragging an item sometimes opens a hole as I drag, and sometimes not. It's hit or miss.

Would it really be too difficult to detect that I have dragged and dropped an item on top of another item and then move that item into the position where I dropped it (adjusting any other items that might need to be moved to make room)?

The 'hole' - or insertion point - will open up everytime a dragged item is over the narrow space between two shelf/dock icons. I think that, in your case, increasing horizontal icon spacing will make this space wider and therefore easier to create an insertion point.

The reason your suggestion isn't pheasible is because WorkShelf has the ability to open documents by dropping the document directly into an application's icon in a shelf or dock. For instance, imagine you have a MS Paint item on a shelf - dragging & dropping a JPG file on top of the MS Paint icon (i.e.; over the actual icon instead of into the space between icons) will open that JPG file in MS Paint.

Jorge:

I don't see why the drag of an item onto an icon should cause a big problem. The current drag/drop interface just does not work well. When a shelf is full, I can drag an icon to the right and holes sometimes open up; However, if I overshoot and have to go back, the holes never open up. This problem is particularly severe if a shelf is completely full.

There are numerous solutions you can have to this and not interfere with those users that drag documents onto icons:

1. Assume exe/dll/com/bat or possibly a list of extensions supplied by the user are not to be considered documents to be dropped on an icon.

2. If a drag operation was initiated by clicking on an existing shelf icon, then assume that the only thing you can do with this drag is drop it into the new position where it is dropped. It should be largely unnecessary to have an icon on a shelf that needs to be dragged to another icon rather than just clicked once and have file associations open the correct program.

3. Provide a simple dialog box accessible from a button on the "Shelf Properties" dialog that lists all the icons on the shelf with buttons providing for move up/move down and maybe delete and/or new as a convenience.