After an upgrade to Joomla 3.8.13 and Civi 5.6.0 the Joomla admin menu dropdown is stacking under the Civi menu. I can't reproduce on https://joomla.demo.civicrm.org as even if the versions weren't 3812 and 560, the Joomla admin menu isn't long enough.
I can confirm that restoring the z-index that was removed in root/administrator/components/com_civicrm/civicrm/css/joomla.css corrects this issue. The rest of the removed code makes no difference. This works for me:
ul#civicrm-menu {
z-index: 1;
position: relative;}
There was a commit that fixed css for shoreditch theme probably that might have caused the regression in Joomla. Can you try to replace the code from the commit and see if it works? If so I can file a issue and submit the patch for regression.
I checked my joomla.css and the z-index lines are already there but i still can't see the administrator menu any more:
text-align:left; }
/* Joomla Admin Menu alterations / / Moved from civicrm.css in v3.2 */
ul#civicrm-menu { position:relative; z-index: 1; }
div#toolbar-box div.m { padding: 0px !important;
Anything else I can try please?
