What do you mean under "GUI example"?
I give you the link on the site.
http://www.tcreator.classic-ru.org/
You can find there three programs: one free, two commercial. All of them - GUI. On site you can find documentation for programs.
All tour examples was created with them.
As for you task, Hotspot editor from panoVideo Creator and touCreator light allows to add, edit and delete hotspots. But it have much more functions then krpano's tour_editor html.
In krpano you can add only icon hotspot (one image for all tour) and order only one function - load scene.
Hotspot editor can add icon, image, textfield, polygonal and optionally - flyout types of hotspots.
For example as image or icon hotspot you can use any image. And for each hotspot you can select individual image Addfitionally you can select scale and alpha. For distorted hotspots you can rotate them over x, y and z axis.
You can combine text and image for textfield hotspots. Prepare or use ready html page.
Place polygonal hotspots in html 5.
Set start position, scale and alpha for flyout hotspots.
You can order any action for this hotspots. Not only 7 pre-build but also any custom.
More then: you can edit at any moment the position, appearance, content and actions for ready hotspot.
Or simply delete hotspot and create new.
And it is not all.