It is possible to toggle the CTI pop-up menu via each terminal individually.
Temporarily Hiding CTI Pop-Up Menu
Simply select the icon on the bottom left corner of the menu to hide it like the below image.
You may select the same icon again, to show the menu again.
Deleting Certain Call Entries From CTI Menu List
Click on the icon to clear the particular call entry from the list.
※ You may clear the entries where calls have already been completed to keep your list clean.
However, doing so on one terminal, will cause the removed entries to also disappear from all