Hi.
First of all, in screenshot you provided you included also menu with titlebar. This is wrong, as those are two different objects.
Themes may be a solution to that question. But it may not be what you want.
If you want more information about themes, look at the following links:
New UI theme - - What's New (appeon.com)
Enhanced UI Theme - - What's New (appeon.com)
For window object you do have the following declaration in theme.json that is related to title:
"title":
{
"active-state":
{
"background-color":"#FFFFFF",
"text-font":{"color":"#000000"}
},
"inactive-state":
{
"background-color":"#FFFFFF",
"text-font":{"color":"#999999"}
}
},
Background color is what needs to be modified.
But this would affect all windows. To make it affect only the frame you should disable all other controls and add a section for the specific object you open as frame:
"w_your_frame_control": // here you should add all the code from window and modify title...
{
...
//Copy the settings from the "window" node
//of the "theme.json" file and then modify.
}
Setting "drawing":false to all other controls will disable them... But for your frame you should be able to customize all available parts in json file.
Andreas.