function SimpleCheckbox(opts) {
            var _this = _super.call(this) || this;
            _this._opts = opts;
            _this._domNode = document.createElement('div');
            _this._domNode.className = 'monaco-checkbox';
            _this._domNode.title = _this._opts.title;
            _this._domNode.tabIndex = 0;
            _this._checkbox = document.createElement('input');
            _this._checkbox.type = 'checkbox';
            _this._checkbox.className = 'checkbox';
            _this._checkbox.id = 'checkbox-' + SimpleCheckbox._COUNTER++;
            _this._checkbox.tabIndex = -1;
            _this._label = document.createElement('label');
            _this._label.className = 'label';
            // Connect the label and the checkbox. Checkbox will get checked when the label recieves a click.
            _this._label.htmlFor = _this._checkbox.id;
            _this._label.tabIndex = -1;
            _this._domNode.appendChild(_this._checkbox);
            _this._domNode.appendChild(_this._label);
            _this._opts.parent.appendChild(_this._domNode);
            _this.onchange(_this._checkbox, function (e) {
                _this._opts.onChange();
            });
            return _this;
        }
If 'selection find' is ON we should not disable the button (its function is to cancel 'selection find').
If 'selection find' is OFF we enable the button only if there is a selection.