The "Use Operating System theme" option makes sure an Web Application responds to the light or dark theme settings of the operating system, which is really a bonus. However, in some cases a single control may need a specific (color) setting, which doesn't seem possible.
In my case, I have a TWebPanel, which must show a particular color, depending on a status. Without the "Use Operating System theme" option, this is simply done by setting the color. With the "Use Operating System theme" option, I though I had to define an elementClassName and define the color as a CSS class.
However, I can't change the color of a TWebPanel through CSS, with or without setting the "Use Operating System theme". I can do this for buttons and I wonder if this is possible for panels too, as a panel is a container control. However, when checking the "Elements" of my user interface, I see a panel has a background-color attribute?
Attached a small program showing the differences: click the change button to see a difference between active and passive status. Nothing is happening on the panels when setting the Use Operating System theme" option.
OSTheme.zip (7.1 KB)