CBN_ERRSPACE
idComboBox = LOWORD(wParam);
hwndComboBox = (HWND)lParam;
The CBN_ERRSPACE notification message is sent when a combo box cannot allocate enough memory to meet a specific request. The parent window of the combo box receives this notification message through a WM_COMMAND message.
idComboBox
Value of low word of wParam. Specifies the combo-box ID.
hwndComboBox
Value of lParam. Specifies the combo-box window handle.
WM_COMMAND