grafana/public/app/plugins/panel/text/editor.html

<div class="gf-form-group">
	<div class="gf-form-inline">
		<div class="gf-form">
			<span class="gf-form-label">Mode</span>
			<span class="gf-form-select-wrapper">
				<select class="gf-form-input" ng-model="ctrl.panel.mode" ng-options="f for f in ['html','markdown','text']"></select>
			</span>
		</div>

		<div class="gf-form" ng-show="ctrl.panel.mode == 'text'">
			<span class="gf-form-label">Font Size</span>
			<span class="gf-form-select-wrapper">
				<select class="gf-form-input" ng-model="ctrl.panel.style['font-size']" ng-options="f for f in ['6pt','7pt','8pt','10pt','12pt','14pt','16pt','18pt','20pt','24pt','28pt','32pt','36pt','42pt','48pt','52pt','60pt','72pt']"></select>
			</span>
		</div>
	</div>
</div>

<h3 class="page-heading">Content</h3>

<span ng-show="ctrl.panel.mode == 'markdown'">
	(This area uses <a target="_blank" href="http://en.wikipedia.org/wiki/Markdown">Markdown</a>. HTML is not supported)
</span>

<textarea class="gf-form-input" ng-model="ctrl.panel.content" rows="20" style="width:95%" ng-change="ctrl.render()" ng-model-onblur>
</textarea>