#9 labels blink when ref completed.

[Jens Egeblad]

If I written pressed \ref{subsec.placement} then upon completing the
final }, it would be nice if the subsection containing the
label{subsec:placement} would blink in the tree view.

Is this possible. Becuase it would be a nice feature. This way one can
see if it is in fact the correct subsection.