Copied from the RTP Analysis dialog, just like the GTK+ version.
Change-Id: I111020bc4073a3a3ba583bdace51a91ee5fef300
Reviewed-on: https://code.wireshark.org/review/10447
Petri-Dish: Gerald Combs <gerald@wireshark.org>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>