Missing image warning

Hi all,

I'm getting the following warning in a debug build of master:

warn:legacy.osl:28252:1:vcl/source/gdi/bitmapex.cxx:109:
BitmapEx::BitmapEx( const ResId& rResId ): could not load image
<svx/res/notcertificate_16.png> via icon theme tango.

The BitmapEx constructor that utilizes resources is trying to locate this,
but calls on ImplImageTree::loadImage with the default parameter
loadMissing set to false, which means it doesn't substitute a default image
for the missing PNG.

Can someone explain how the icon themes are meant to work? How does it
detect tango as the theme and is there meant to be fallback code?

Also, can we repackage the tango theme to include this image? It's being
called by a security statusbar I believe, but I have no idea where abouts
this is in the UI for writer.

Thanks,
Chris