TB_INDETERMINATE  1JHKPC0 

The TB_INDETERMINATE message sets or clears the indeterminate state of the specified button in a toolbar.

TB_INDETERMINATE

wParam = (WPARAM) idButton;

lParam = (LPARAM) MAKELONG(fIndeterminate, 0);

Parameters

idButton

Command identifier of the button whose indeterminate state is to be set or cleared.

fIndeterminate

Indeterminate flag. If this parameter is TRUE, the indeterminate state is set. If it is FALSE, the state is cleared.

Return Values

Returns TRUE if successful or FALSE otherwise.