same error occurs for me in fedora 24
Just wanted to confirm that I am seeing the exact same problem with the KDE plasma taskbar in fedora 24.
Not sure if anyone has seen any fixes for this situation, since this thread was posted.
I am hoping that someone will know why the panel/taskbar can't be autohidden.
I try going to the panel/taskbar controls, but when I try to click on one of the options on the "more settings..." submenu - the menu disappears.