Statechart Checks : (C1041) Or states without a default entrance

(C1041) Or states without a default entrance

There are states of type “or” (decomposed into exclusive states) with entering transitions but with no “default” entrance.
Error In:
Correctness
Example:
In the following figure, S1 is an or state consisting of S2 and S3. A transition triggered by event E enters S1, but because S1 has no default entrance, the actual target of this transition is not defined.
Erroneous Elements:
States