Microsoft didn't make it easy for old school desktop programs like xplorer² to change window colors, so you will discover a number glitches, remnants of the default white-ish system colors here and there (e.g. sorry about the main menu bar). In general things look best for windows 10.
You can tell which pane is active by its slightly brighter dark background. Inactive panes are pitch black. If you need more distinct identification of inactive panes, select a background color from Tools > Options menu, but that is liable to upset the darkness. Alternatively tick the advanced option "Highlight active pane's titlebar as in 2xExplorer".
To make your windows 10 active window titlebar blue (which is better than white) use this tip (accent color setting)
Other additions of note include: (see the changelog for the full list)
The regular expression matches any 2 groups of characters separated by un underscore _, and the brackets define 2 groups. Inverting the backreferences $2-$1 effectively swaps the order of the words in the filename. See the colors in the above table to help you understand what matches with what. Parts of the filename that weren't matched, e.g. the extension, remain the same. For more information on the regular expression syntax see the documentation and watch the demo video below
Please use Help > Check for updates menu command or the equivalent from ribbon's File leftmost tab to get the new version. If you don't have xplorer² installed try the download page for your free trial.