BUG: load blocks closed by default?

That should be enough editor.Blocks.getCategories().forEach(ct => ct.set('open', false)) but categories are not created until the render of blocks (which happens, by default, when you click the Blocks tab) so you just need to execute that script once are rendered.

Hello, i have made it to close all blocks in one plugin, try to adapt to you.:

export default (editor, opt = {}) => {
    const Commands = editor.Commands;

    Commands.add("dina:hide-all-blocks",(editor)=>{
        editor.Panels.getButton("views","open-blocks").set("active",1);
        let categories = editor.BlockManager.getCategories().models;
        categories.map(elem=>{
            elem.view.$el.css("display","none");
        });
    })
};

const Commands = editor.Commands;

    Commands.add("dina:hide-all-blocks",(editor)=>{
        editor.Panels.getButton("views","open-blocks").set("active",1);
        let categories = editor.BlockManager.getCategories().models;
        categories.map(elem=>{
            elem.view.$el.css("display","none");
        });
    })

still the same here jsfidle : https://jsfiddle.net/46mfqeht/