Only the help contents tree is styled

I'm using Vcl Styles Utils in a project that uses a dark style. I have a CHM help file associated with my project. However, the help window is completely deformed:

Observe the following issues:

The only thing in the window that's implementing styles of any kind is the contents tree on the left (nothing else has styles applied)
Approximately 20-30 pixels of the main toolbar at the top are chopped off by the Windows title bar (probably a calculation based on the VCL Style toolbar height)
Text in actual help file which should be black changes with style (for example on dark style, black text becomes white and unreadable)

My uses clause has the following:

  Vcl.Styles, Vcl.Themes,
  Vcl.Styles.FontAwesome,
  Vcl.Styles.Fixes,
  Vcl.Styles.Utils.Menus,
  Vcl.Styles.Utils.Forms,
  Vcl.Styles.Utils.StdCtrls,
  Vcl.Styles.Utils.ComCtrls,
  Vcl.Styles.Utils.ScreenTips,
  Vcl.Styles.Utils.SysControls,
  Vcl.Styles.Utils.SysStyleHook,

RRUZ / vcl-styles-utils

Only the help contents tree is styled #251