Window procedure recives no tooltip notifications

When a window and its window procedure are located in a DLL and the window contains a toolbar,
and the toolbar contains the TBSTYLE_TOOLTIPS style, the toolbar's parent window should recive
tooltip notification messages like TTN_GETDISPINFO, TTN_SHOW and TTN_POP. However, when
the mouse is moved over a toolbar button, the window recives NM_TOOLTIPSCREATED, but after
that, it seems that it doesn't get any further notifications regarding to tooltips.