Rewrite ForceVariableDialog. It's not based on wx.TextEntryDialog
Don't customize standard wx.TextEntryDialog on the fly, implement your
own dialog for that with expected behavior and without any hacks.
<xsd:element name="Xenomai">
<xsd:complexType>
%(toolchain_gcc)s
<xsd:attribute name="XenoConfig" type="xsd:string" use="optional" default="xeno-config"/>
</xsd:complexType>
</xsd:element>