Problem affects on dashboard "Problems by severinity". When You are trying to click on the any hostname doesn't appear any window on it.
Problem is in CSS style, which is generated by main.jsscript in /usr/share/zabbix/js/main.js
Replacing 1001 of parameter "zIndex" resolves this issue
I have replaced on "10" value
After that my popups works well!!!
Hello from Russia, Surgut city =)