In 4.4 most controls are now either custom drawn, massively hacked or written from scratch to support custom colors and/or borders.
Toggling dark mode changes the colors for all controls which does not have a color option and Titlebars in all open dialogs, in real time.
Dark mode is enabled by default if windows dark mode is enabled, it can be toggled Automatic/On/Off in Options -> Colors.
See also on DARKMODECHANGED, $darkmode.
Channel Editor Topic preview uses the Topicbox background and text color to simulate how the topic with colors will look.
Channel List uses the message area background and text color to accurately show topic with colors.
Theme Manager theme preview uses the colors from the theme to accurately show the preview.
The current dark mode colors are set to make things looks apart and reduce brightness, they will be tweaked based on feedback.
It is not possible to change the selection color of textboxes and possibly other controls.
It is not possible to change the colors of scrollbars, a custom scrollbar can be made from scratch, but it would only be useable by controls created from scratch.
It does not seem to be possible to change or draw the datetime picker dropdown, a custom one could be made, but seems unnecessary for just one single use case (Create client SSL/TLS certificate).
Save/open/browse folder/file dialogs are controlled by windows and will only be dark when windows have dark mode enabled.
Titlebars are only dark when dark mode in windows is enabled. AdiIRC will change them automatically when dark mode is enabled in both windows and AdiIRC.
It is currently not possible to change the colors of Titlebars for MDI windows.
Scripted Dialogs are currently excluded from dark mode, except the Titlebar.
Figure out a reasonable color to use for link controls and installed dictionaries in "Add Dictionaries" dialog.
Add option to set a custom font for all controls which does not currently have a font option.
Change the individual control colors based on feedback.
Look into whether it's possible to custom draw or use a image for up/down arrows on numeric uo/down to something with more light grayish colors?
Look into whether it's possible to custom draw or use a image for down arrow on dropdowns to something with more light grayish colors?
Options to change the dark mode colors to something custom?
Some controls can be custom drawn with a custom selection color, not sure if it's worth it?
Custom scrollbars for custom created controls?
Apply dark mode to scripted dialogs?