Dynamics 365 for Finance and Operations: More Than One Form Was Opened at Once for the Lookup Control

[FormControlEventHandler(formControlStr(VendCertification, StateId), FormControlEventType::Lookup)]
public static void StateId_OnLookup(FormControl sender, FormControlEventArgs e)
{
// Declare and initialize new variable.
FormControlCancelableSuperEventArgs formControlCancelSuper = e as FormControlCancelableSuperEventArgs;

//Custom lookup code can go here.

// Cancel the super call of lookup control.
formControlCancelSuper.CancelSuperCall();
}