How to get the "inside" of a tab control, i.e. the area in which you can place controls?
// doesn't work:
WINDOWINFO tabsInfo;
GetWindowInfo(GetDlgItem(hwndDialog, IDC_TABS), &tabsInfo);
MoveWindow(someHwnd, tabsInfo.rcClient.left, tabsInfo.rcClient.top, ...
tabsInfo.rcClient gives the entire region used by the tab control, including its own controls