  In this paper, we revisit the problem of using gravitational wave data to
test the Einstein-dilation-Gauss-Bonnet theory, by using nine selected
gravitational wave events from GWTC-3. Compared with existing work, we are
taking into account the higher harmonics more properly and we also study the
contribution of the merger-ringdown data. Using the inspiral data alone, we
find that the best result is from GW200115, giving $\sqrt{|\alpha|} < 1.1$ km,
which is about 17\% tighter than the previous best result. We also notice the
possible existence of a simple unexpected relation among the constraints from
different events. Several combinations of the selected events give
$\sqrt{|\alpha|} \leq 1.0$ km. The result is further improved when the
merger-ringdown data is also included, using two phenomenological schemes,
giving $\sqrt{|\alpha|} < 0.87$ km for GW200115 in the best case scenario.
