Open windows don't show up on task bar -

When I open an .odt or .ods file (or .doc or .xls), the file opens, but doesn’t show in the task bar. If I open the Write or Base from the menu, then open the file, it shows up fine.

This makes productivity difficult if I unthinkingly minimize the window, and I’ve already accidentally had the same file open twice without realizing it.

I’m running Linux Mint 17.3, LibreOffice Version: Build ID: 1:5.3.1-0ubuntu1~trusty0.

How can I get my task bar indicators back?!?!?