In the Mate GUI (Linux Mint), my icons by the time are only given half the space of the entire panel / task bar. It really looks like that division of the panel is meant to be much smaller.
Obviously, they don't need all that space. The open program tabs do, however, and they are left with only half the space, on the left.
There is a little gray divider line (three tiny gray dashes). How can I drag it or otherwise unlock/move it?