style "(empty)" option differently to distinguish from regular tag values

css/80_app.css

@@ -2406,6 +2406,11 @@ div.combobox {
     color: #333;
 }
 
+.combobox .combobox-option.virtual-option {
+    font-style: italic;
+    color: #333;
+}
+
 .form-field-input-wrap {
     position: relative;
 }

modules/ui/sections/raw_tag_editor.js

@@ -416,6 +416,9 @@ export function uiSectionRawTagEditor(id, context) {
                             return {
                                 value: ' ',
                                 title: t('inspector.empty'),
+                                display: selection => selection.text('')
+                                    .classed('virtual-option', true)
+                                    .call(t.append('inspector.empty'))
                             };
                         }
                         return {