<p>A simple problem: If i use escape characters for a property such as</p>

<pre><code>&lt;mx:Image  id="img" toolTip="\\foo{\\bar}"
</code></pre>

<p>It wont validate toolTip and therefore not compile.</p>

<p>What is the solution ?</p>

You can use ActionScipt for example in a creationComplete event handler and assign you tooltip and you won't have the same constraints as in MXML.
But you also can avoid these constraints in MXML by using CDATA:
```
```
<mx:Image id="img" source="foo.jpg" width="50" height="50">
<mx:toolTip>
    <![CDATA[\foo{\bar} or any usually forbidden characters as <, >, &, "'"...]]>
</mx:toolTip></mx:Image>
```
```