Can't Shrink DOpus Window

I am currently running version 11.7 and have noticed that on occasion Dopus will not allow a change from full-screen mode.

I normally run Dopus in a shrunken window on my desktop. When I want to preview files I will maximize the program and open the Viewer Pane on the bottom half of the screen. When I get done previewing files I close the Viewer Pane and then either double-click the title bar or click on the middle icon in the upper right-hand corner.

Normally,Dopus returns to the previous window size, but occasionally the program will remain full-screen. The only way to "fix" this is to close the lister and open a new one.

This happened again this morning after viewing several PDF files. As I said, this happened so intermittently that I haven't been watching for a pattern. (And I am in and out of Dopus all day.)

This is a known issue?

Is the window remaining maximized, or is it turning into a movable and resizable window that happens to take up the whole screen?

e.g. Can you drag the window around and resize it?