I have written a patch that displays number of elements (total, with/without problems) in the bottom left corner of a network map. Patch should be applied to Zabbix pre-1.8.4rc1 22 Sep 2010 nightly build and probably later versions.
P.S. Problems are events with severity > 3, warnings are events with 0 < severity <= 3.
P.S. Problems are events with severity > 3, warnings are events with 0 < severity <= 3.