I did some modify to [email protected] applet to add rag and drop functionality:

I added this to class ApplicationButton extends GenericApplicationButton { …

    handleDragOver (source, actor, x, y, time) {  
        //global.log("X=",x," Y=",y);  
        //let button=source;  
        //global.log(button.category);  
        this.actor.style_class = "menu-category-button-selected";  
    }  
    handleDragOut() {  
        global.log("YY");  
        this.actor.style_class = "menu-category-button";  
    }  
    acceptDrop (source, actor, x, y, time) {    // Modifica TOMMASO
        //global.log("Cat X=",x," Y=",y);
        let button=source;  //Bottone spostato
        //global.log("CAT ",button.category," ",button.name," ",button.position);
        //global.log("CAT act",this.category);
        button.category=this.category;
        let parent = this.actor.get_parent();
        //global.log("parent=",parent.name);    // applicationsBox
        //parent.insert_child_below(button.actor,this.actor);
        let parentParent = parent.get_parent();
        //global.log("parentParent=",parentParent.name);    // applicationsScrollBox
        let parentParenParent = parentParent.get_parent();
        //global.log("parentParenParent=",parentParenParent.name);  // categoriesApplicationsBox.actor
        let nn=parentParenParent.categoriesBox;
        //global.log("parentParenParentParent=",nn.name);   // CinnamonMenuApplet -- 1206
        let actors =nn.get_children();
        for (let i = 0; i < actors.length; i++){
            let actor = actors[i];
            //global.log(actor.idx," ",actor.menu_id," ",actor.name);
            if (actor.menu_id==this.category){
            this.applet._select_category2(actor.menu_id);
        }
        // actor.style_class = "menu-category-button-selected";     //Evidenza il pulsante passandoci sopra         
            //actor.remove_style_pseudo_class("hover")
            //actor.style_class = "menu-category-button";
            //actor.show();
        }       
        //parentParenParentParent._CategoryButtons[3].activate();
    }

I added this to class CategoryButton extends SimpleMenuItem { ...
`    acceptDrop (source, actor, x, y, time) {   // Modifica TOMMASO
        global.log("Cat X=",x," Y=",y);
        let button=source;
        global.log("CAT ",button.category," ",button.name," ",button.index);
        global.log("CAT act",this.label);
        button.category=this.label.text;
    }
    handleDragOver (source, actor, x, y, time) {
        this.activate();
    }
I inserted this into _display function:
    this.categoriesApplicationsBox.actor.categoriesBox=this.categoriesBox;

I added this function under _select_category:

    _select_category2 (name = null) {
        this.lastSelectedCategory = name;
        this._displayButtons(name || 'app');
        this.closeContextMenu(false);
        this._scrollToButton(null);
    }

Now I can drag an application button to other categories.

The point is that while I drag, I have some strange artifact on the left panel.

Morever I discovered how highlight buttons but I cannot disable highlights. As you can see I tried with “handleDragOut”, but no success.

    handleDragOver (source, actor, x, y, time) {
        global.log("X=",x," Y=",y);
        let button=source;
        global.log(button.category);
        this.actor.style_class = "menu-category-button-selected";   
   }
    handleDragOut() {  
        global.log("YY");  
        this.actor.style_class = "menu-category-button";  
    }  

I had to discover how to do these things with “try and error” method because I cannot find good and exaustive documentation about Cinnamon Applets.

Where could I find Cinnamon Applets reference ?

I would like to save changes of the menu in some file, but at the moment I’ve no idea…

Thank you