Hide or disable flat form option

Hi Brendan,
 
Thank you for posting your question.
 
Since the Options pop-up window is a part of the Flexmonster Toolbar, you can modify the content of the Options tab with toolbar customization. Please check out the following page for more info: https://www.flexmonster.com/doc/customizing-toolbar/
 
In this particular situation, to disable the flat view in the options window you would need to modify the showOptionsDialog function defined in the flexmonster.toolbar.js file. More specifically, to hide the flat form radio button, the following code block (on line 2037) needs to be removed:
 

if (options != null && options.hasOwnProperty("dataSource") &&
    !(options["dataSource"]["type"] == "microsoft analysis services" ||
        options["dataSource"]["type"] == "mondrian" ||
        options["dataSource"]["type"] == "elasticsearch")) {

    // layout - flat
    var item = document.createElement("li");
    var itemWrap = document.createElement("div");
    itemWrap.classList.add("fm-radio-wrap");
    var flatViewCbx = document.createElement("input");
    flatViewCbx.type = "radio";
    flatViewCbx.name = layoutGroup;
    flatViewCbx.id = "fm-lt-3";
    flatViewCbx.value = "flat";
    itemWrap.appendChild(flatViewCbx);
    var label = document.createElement("label");
    label.setAttribute("for", "fm-lt-3");
    self.setText(label, Labels.flat_view);
    itemWrap.appendChild(label);
    item.appendChild(itemWrap);
    list.appendChild(item);
}

 
This part of the Toolbar source code is responsible for displaying the flat form option in the pop-up window – if you get rid of it, the flat form option is no longer available.
 
Please let us know if this helps.
 
Best regards,
Mykhailo