Scroll bar on a TForm becomes invisible when changing from legacy Windows style to Windows10 styles

The vertical scroll bar disappears when a Windows10 style has been applied.Reverting to legacy Windows style makes it reappear. When TForm StyleElement seBorder is set to false the scroll bar becomes visible again but this approach kind of nullifies the idea with the style change so it is not an applicable solution. From my app´s functional point of view I need to have the TForm StyleElements seClient to false. As far as I can see, this is, so far, the only style change problem in my app. I am developing a C++ VCL-app using RAD Studio 10.2 Any ideas what is wrong ? B.R./Matsmats.xy.eriksson@ericsson.com