[CentOS-virt] Managing virt-manager's ever growing log file

I'm looking for suggestions on managing the ever growing log file from virt-manager (~/.virt-manager/virt-manager.log). All the info I've read says that the log file is overwritten on each virt-manager startup. That is demonstrably not true, at least for virt-manager-0.9.0-28.el6. I see "virt-manager startup" entries going all the way back to the first time I started it.

So, it looks like some arrangement with logrotate is in order. Does a running virt-manager have any facility for telling it to close and reopen its log file, or do I have to use the "copytruncate" function of logrotate?