How to open two directories in Separate Windows - Side by side

[dontletthesamedogbiteyoutwice]

As the title suggests.

I'm trying to view all the folders and files, say from a WordPress plugin (current vs. updated) in two separate panes that are side by side.
Try what I might, I can't seem to find the setting.
Currently, I see a tree view on the left side that indicates if the files or folders are identical or not, but I'd like to see each tree side by side. What I see is, The right side of the screen is empty. The toolbar does show the different directories.

[sdottaka]

Unfortunately, WinMerge currently does not support such a display.

[ELY3M]

any plans to support that display?