cannot edit events front end-screen dims no popup

Have been unable to edit events from the front end. screen dims, but no popup appears. I can make it appear, somewhat, by tinkering with css in chrome viewer. but actually changing the css, does not work. can however create new events. this has been going on for some time, possibly when we converted from joomla 1.5
we are using a modified optimus template. the popups are visible when i try a different template, but of course the site looks terrible!
using joomla 3.7.4, jevents 3.4.39 have turned off front end edit in popup.
here is a link:
http://eldoradosf.org/icalrepeat.detail/2017/9/20/22107/ecia-board-working-meeting.html?pop=1

further info:

PHP Version : 5.6.31

MySQL Version : 5.6.36-82.1-log

Server Information : Linux siteground195.com 3.12.18-clouder0 #85 SMP Mon Apr 3 10:28:14 EEST 2017 x86_64

Fix jQuery? : Yes

Load JEvents Bootstrap CSS? : Yes

Max Input Vars ? : 3000

Club code set? : No  

User Agent : Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36  

Joomla : 3.7.4

component_com_jevents : 3.4.39

component_com_sh404sef : 4.4.6.2271

component_com_jce : 2.6.18

component_com_comprofiler : 2.1.3

module_mod_jevents_cal : 3.4.39

module_mod_jevents_custom : 3.4.39

module_mod_jevents_filter : 3.4.39

module_mod_jevents_latest : 3.4.39

module_mod_jevents_legend : 3.4.39

module_mod_jevents_switchview : 3.4.39

plugin_content_jevents : 3.4.39

plugin_finder_jevents : 3.4.39 (not enabled)

plugin_installer_jeventsinstaller : 3.4.39 (not enabled)

plugin_search_eventsearch : 3.4.39

plugin_system_gwejson : 3.4.39