When I start zexplorer it is full-screen and at the top right corner I see 5 icons. From left to right they are: black oval (maybe it's a circle), black triangle pointing up, the normal minimize icon ...
I see another report that "minimize to task bar doesn't work". It's more general than that. If I minimize the window the only way I can find to get it back is to close the program and start over. Also ...