Author: Tomas Rutkauskas 

I need to show some information to the user when the mouse moves over the icon in 
the tray sector. I am using the Shell_NotifyIcon funtion with NIM_ADD, NIM_DELETE 
parameters to show or not show the icon. How to show that hint?

Answer:

It is automatic, you only need to tell Shell_NotifyIcon which hint to use.

1   {Update the tray icons tooltip}
2   
3   procedure UpdateTrayTip;
4   var
5     nim: TNotifyIconData;
6   begin
7     FillChar(nim, sizeof(nim), 0);
8     nim.cbSize := Sizeof(nim);
9     nim.Wnd := wnd;
10    nim.uID := ICONID;
11    nim.uFlags := NIF_TIP;
12    StrLCopy(nim.szTip, GetTrayTooltip, Sizeof(nim.szTip) - 1);
13    Shell_NotifyIcon(NIM_MODIFY, @nim);
14  end;


GetTrayTooltip is a function that in my case returns a PChar pointing at an entry in a constant array of Pchars. You can use StrPLCopy if you have a String holding the tooltip instead. You can set the tip on NIM_ADD as well.