Comment 99 for bug 19250

This semi works (popup.xml):

   <binding id="tooltip" extends="chrome://global/content/bindings/popup.xml#popup">
     <content>
- <children>
- <xul:label class="tooltip-label" xbl:inherits="value=label,crop"
crop="right" flex="1"/>
- </children>
+ <xul:label style="white-space: pre;" class="tooltip-label"
xbl:inherits="xbl:text=label,crop" crop="right" flex="1"> </xul:label>
+ <children />

Just the height/width is still messed up, for which Neil has a (albeit somewhat
ugly) workaround. Not sure why the original code had the anon content inside
the <children> tag though.