If the system PATH environment variable changes, we need to call an undocumented Windows Shell function to rebuild our own Environment block such that new consoles/apps we spawn will see the new PATH.

RefreshEnvironment.pas

   // Add to the Private section of your main form's type declaration.
   Procedure WMSettingChange(Var MSG: TMessage); MESSAGE WM_SETTINGCHANGE;

// If the system PATH environment variable changes, we need to call an
// undocumented Windows Shell function to rebuild our own Environment
// block such that new consoles/apps we spawn will see the new PATH.
Procedure TMain.WMSettingChange(Var MSG: TMessage);
var hLib: THandle;
    pfnRegenerate: Function (oldEnv: Pointer; regenCurrent: BOOL): BOOL; StdCall;
    pNil: Pointer;
Begin
    if (MSG.LParam = 0) then Exit;
    OutputDebugString(PChar(Format('WM_SettingChange in area "%s"', [PChar(MSG.LParam)])));
    if (0 <> StrComp(PChar('Environment'), PChar(MSG.LParam))) then Exit;
    hLib := LoadLibraryEx('shell32.dll', 0, 0);
    if (hLib = 0) then Exit;

    pfnRegenerate := GetProcAddress(hLib, 'RegenerateUserEnvironment');
    if (Assigned(pfnRegenerate)) then
    Begin
        pNil := nil;
        pfnRegenerate (@pNil, true);
        OutputDebugString('SlickRun Process Environment Block updated.');
    End;
    FreeLibrary(hLib);
End;