Ghost/ghost/admin/app/components/modals/edit-newsletter.hbs

<div class="modal-content">
    <div class="modal-body modal-fullsettings">
        <div class="modal-fullsettings-body gh-newsletters-labs">
            <div class="modal-fullsettings-sidebar">
                <div class="flex items-center justify-between">
                    <h2 class="modal-fullsettings-heading">
                        {{if @data.newsletter.isNew "Create" "Edit"}} newsletter
                    </h2>
                    <div class="gh-btn-group">
                        <button type="button" class="gh-btn gh-btn-icon {{if (eq this.tab "settings") "gh-btn-group-selected"}}" {{on "click" (fn this.changeTab "settings")}}><span>Settings</span></button>
                        <button type="button" class="gh-btn gh-btn-icon {{if (eq this.tab "design") "gh-btn-group-selected"}}" {{on "click" (fn this.changeTab "design")}}><span>Design</span></button>
                    </div>
                </div>

                {{#if (eq this.tab "settings")}}
                    <Modals::EditNewsletter::Settings
                        @newsletter={{@data.newsletter}}
                        @optInExisting={{this.optInExisting}}
                        @setOptInExisting={{this.setOptInExisting}}
                    />
                {{else}}
                    <Modals::EditNewsletter::Design @newsletter={{@data.newsletter}} />
                {{/if}}
            </div>

            <div class="modal-fullsettings-main">
                <div class="modal-fullsettings-main-topbar">
                    <button class="gh-btn mr3" type="button" {{on "click" @close}}>
                        <span>Cancel</span>
                    </button>

                    <GhTaskButton
                        @buttonText="Save and close"
                        @successText="Saved"
                        @task={{this.saveTask}}
                        @idleClass="gh-btn-primary"
                        @class="gh-btn gh-btn-icon"
                        {{on-key "cmd+s" this.saveViaKeyboard priority=1}}
                        data-test-button="save-newsletter"
                    />
                </div>
                <Modals::EditNewsletter::Preview @newsletter={{@data.newsletter}} />
            </div>
        </div>
    </div>
</div>