Problem adding icon to run an external program

Today I was trying to add to my DOpus 11 toolbar an icon that launches an external program (HyperSnap). I've done this several times in the past. For example, I have put a Photoshop icon on my Directory Opus toolbar, and I can then simply highlight a filename and click on the toolbar's Photoshop icon to open the file in Photoshop. According to the Directory Opus 11 Manual, "To add a button that launches an external program, you can simply drag the program's icon (or a shortcut to the program) and drop it on the toolbar." But when I tried to do that today, there seemed to be no place where I could drop the icon. I wanted to place it next to another icon already there, but there was no way to make room for the new icon. Trying to drop it made it seem as if I wanted one of the programs already there to handle it, which of course was not what I wanted. When I tried to drop it on empty space at the right end of the toolbar, I saw a circle with a diagonal line inside it, indicating that it couldn't be dropped. I don't know what I'm doing wrong, since as far as I can tell I'm following the manual's instructions, and I know that I was able to add program icons in the past. I'd be most grateful for some help.

Thanks in advance.

You need to select Customize mode before you can make changes to toolbars.

Duh :blush: . Many thanks, Jon.