I have not used uTorrent for about 3 years now. The sidebar was likely an oversight on my part as iirc I didn't have the sidebar visible because I didn't use it. Lastly, what are the reasons you use version 2.2.1 of uTorrent? This won't help find a solution, but will satisfy my personal curiosity.

and even my web pages all load dark themed (thanks to the 'Dark Background and Light Text' plug-in for Firefox. It took me a while to make my version of uTorrent to be dark themed. I have a lot of unfinished projects on the go, but I do want to try to help you with this as I am a big fan of dark themes and I understand the blinding brightness of a light theme app popping up. I also know that Windows 10 isn't like Windows 7 and earlier for customizing colours (which is why many older uTorrent themes might not work even with older versions of uTorrent in Windows 10). Do you know of a place where uTorrent version 2.2.1 (64 or 32 bit?) can still be safely downloaded? Also what OS (and version) are you running? I recall that at some point uTorrent changed colour codes and such. To remove these colours and return to you default colours, simply search in Windows for the file named 'current.btskin' and rename it to '' Note: Some lighter areas will remain (slide bars, top menu bar, and a few other bars (about 4 in total). Then double click the file,or drag it and drop it onto uTorrent. Save that file as 'uTorrentDarkness.btskin' (or whatever you want, just use the extension '.btskin'. Copy the text below, paste it into 'NotePad' Save the file as plain text with the file name 'btskin' no extension, just 'btskin'.

You can try this option: I made this 'theme' myself and currently use it with version 3.5.5.

Utorrent 2.2.1 settings