If you are looking to hide certain buttons from the Calendar Details pop-up create a simple VF page and include following code just below the <apex> tag
<apex:page showHeader="true" showChat="false" sidebar="false">
<SLCA2:calendar namespace="SLCA2"
calendar=""
createable=""
urlparams=""
>
<style>
div.CA_popup div.CA_event_detail div.buttons > span[data-action="edit"],Â
div.CA_popup div.CA_event_detail div.buttons > span[data-action="Details"],Â
div.CA_popup div.CA_event_detail div.buttons > span[data-action="Close"],Â
div.CA_popup div.CA_event_detail div.buttons > span[data-action="delete"],Â
div.CA_popup div.CA_event_detail div.buttons > span[data-action="menu"] {
 display:none;
}
</style>
</SLCA2:calendar>
Â
</apex:page>
Just remember that copying this example code will remove ALL buttons from the pop-up. Be sure to include only those buttons that you need to hide.