Add a breakline in tooltip

Another approach that I find useful is to embed 
 in the tooltip. The Tooltip will then have a Linebreak at this point. For example

ToolTip="Host name or IP address of the server. Click the 
Find Server button to help obtain the correct entry."

This allows the xaml code to be more concise, but perhaps less readable. More details at Newline in string attribute.

<Label>
  <Label.ToolTip> 
     <TextBlock>
          Lorem ipsum dolor sit amet,
          <LineBreak /> 
          consectetur adipiscing elit. 
      </TextBlock> 
  </Label.ToolTip> 
</Label>
  ....