Some UI elements can't be themed

I’m in the process of trying to create a new theme, but it seems that some elements cannot be re-colored through the Custom Theme color options. This makes it very annoying to try and create a dark color theme, as the un-themeable elements retain their default light color theme, which is quite an eyesore in contrast to the intended dark palette. The first thing I did in creating my theme was to blank out all of the colors and buttons like so, so that I could start to go through one color at a time and figure out where they were used in the UI (the names in the ImageCache.htm tooltips help, but some of the names don’t always exactly line up with the actual usage), which very clearly highlights the parts of the UI that can’t seem to be recolored.

Here is my blanked out ImageCache.png:
ImageCache.png
And here is the result:
audacity_unthemed_elements.png
As you can see, there are several UI elements which retained their default coloring, such as the main menu, scrollbars, drop-down menus, toolbar spacer lines, context menus, and the bottom window status bar. I’m only able to test the Windows version, so I’m not sure if the same is true for the Mac and Linux builds.

OS: Windows 10, Version 1803 (Build 17134.165)
Audacity Version: 2.2.2

Elements that can’t be themed are (mostly) those parts that are native to the system on which it is running. To get a nice looking dark theme for Audacity, you need to have a dark theme for your Desktop.

Example, here is the built-in dark them for Audacity 2.2.2 on Linux, first with a light Desktop them, then with a dark Desktop theme:
windowplus000.png
windowplus001.png

I’m using the Windows 10 dark theme, both with and without the “Blend system and Audacity theme” option selected.

Ditto

I rarely use Windows, but last time I looked, Windows 10 themes seemed to be broken - most apps were not properly themed. When you have the Windows 10 dark theme enabled, do other applications appear properly themed?

Selecting “blend system and Audacity theme” in Audacity preferences does have some effect …

2-2-1  ''blend' darkens lite-theme, but doesn't darken the spectrogram menu.gif
[ I’m still soldering-on with Windows Vista ]