@TraderBaker To modify the watchlist background color yea you have to modify the theme file.
Open NOTEPAD or any text editor as Administrator. For Notepad just right click on it and go to Run As Administrator..
Then, just go into C:\Program Files\StockstoTrade\Resources\Styles and find "dark" which is a Windows Theme... and open it
then search for <Property name="liveDataTableBackground" and then change the value to whatever you want it to be.. for example if you want it to be white then do
<Property name="liveDataTableBackground" value="#ffffff" />