src/popupwin.c
static void
filter_handle_drag(win_T *wp, int c, typval_T *rettv)
{
    int	row = mouse_row;
    int	col = mouse_col;

    if ((wp->w_popup_flags & POPF_DRAG)
	    && is_mouse_key(c)
	    && (wp == popup_dragwin
			  || wp == mouse_find_win(&row, &col, FIND_POPUP)))
	// do not consume the key, allow for dragging the popup
	rettv->vval.v_number = 0;
}
/*
 * In a filter: check if the typed key is a mouse event that is used for
 * dragging the popup.
 */
In a filter: check if the typed key is a mouse event that is used for
dragging the popup.
In a filter : check if the typed key is a mouse event that is used for dragging the popup .
static void
filter_handle_drag(win_T *wp, int c, typval_T *rettv)
{
    int	row = mouse_row;
    int	col = mouse_col;
    if ((wp->w_popup_flags & POPF_DRAG)
	    && is_mouse_key(c)
	    && (wp == popup_dragwin
			  || wp == mouse_find_win(&row, &col, FIND_POPUP)))
	rettv->vval.v_number = 0;
}
static void filter_handle_drag ( win_T * wp , int c , typval_T * rettv ) { int row = mouse_row ; int col = mouse_col ; if ( ( wp -> w_popup_flags & POPF_DRAG ) && is_mouse_key ( c ) && ( wp == popup_dragwin || wp == mouse_find_win ( & row , & col , FIND_POPUP ) ) ) rettv -> vval . v_number = 0 ; }
In a filter: check if the typed key is a mouse event that is used for
 dragging the popup.
In a filter : check if the typed key is a mouse event that is used for dragging the popup .
// do not consume the key, allow for dragging the popup