UI: Highlight unknown audio device label in settings

UI/window-basic-settings.cpp

@@ -279,6 +279,24 @@ static std::tuple<int, int> aspect_ratio(int cx, int cy)
 	return std::make_tuple(newCX, newCY);
 }
 
+static inline void HighlightGroupBoxLabel(QGroupBox *gb, QWidget *widget,
+					  QString objectName)
+{
+	QFormLayout *layout = qobject_cast<QFormLayout *>(gb->layout());
+
+	if (!layout)
+		return;
+
+	QLabel *label = qobject_cast<QLabel *>(layout->labelForField(widget));
+
+	if (label) {
+		label->setObjectName(objectName);
+
+		label->style()->unpolish(label);
+		label->style()->polish(label);
+	}
+}
+
 void RestrictResetBitrates(initializer_list<QComboBox *> boxes, int maxbitrate);
 
 void OBSBasicSettings::HookWidget(QWidget *widget, const char *signal,
@@ -2096,6 +2114,8 @@ void OBSBasicSettings::LoadListValues(QComboBox *widget, obs_property_t *prop,
 						 "UnknownAudioDevice"),
 					   var);
 			widget->setCurrentIndex(0);
+			HighlightGroupBoxLabel(ui->audioDevicesGroupBox, widget,
+					       "errorLabel");
 		}
 	}