dmn-js opens the first element that can be viewed once the import is done. Typically, this is the DRD. You can change that behavior:
dmnJS.importXML(dmnXML, function (err) {
const views = dmnJS.getViews();
const decisionTableViews = views.filter(
({ type }) => type === "decisionTable"
);
if (decisionTableViews.length === 1) {
dmnJS.open(decisionTableViews[0]);
}
});
CodeSandbox: https://codesandbox.io/s/open-single-decision-table-by-default-n4j5c