SAPUI5: How to generate new Elements based on a ComboBox Option

Hello,

I have the following ComboBox:

<ComboBox items="List with items" width="100%" visible="true" 
textAlign="Initial" textDirection="Inherit" maxWidth="100%">
  <items>
    <core:Item text="Example 1">
      <Label text="Option 1"></Label>
      <Label text="Option 2"></Label>
   </core:Item>
   <core:Item text="Example 2">
   </core:Item>
  </items>
</ComboBox>

I have a comboBox with two Possibilities Example 1, Example 2.

If the User chooses Example 1 -> the Label Text of Option 1 and 2 should drop.

I get the following Error:

What to do to make it function?