Forms >DimensionDefaultingLookup >Methods>init
//Add below code++
qbds = queryBuildDataSource.addDataSource(tableNum(DimensionAttributeValue));
qbds.relations(true);
qbds.joinMode(JoinMode::InnerJoin);
qbds.fetchMode(QueryFetchMode::One2One);
qbds.addLink(dimAttrViewContract.parmKeyFieldId(),fieldNum(DimensionAttributeValue,EntityInstance));
qbds.addRange(fieldNum(DimensionAttributeValue,DimensionAttribute)).value(strFmt("%1",dimAttr.RecId));
qbds.addRange(fieldNum(DimensionAttributeValue,IsSuspended)).value(SysQuery::value(NoYes::No));
ledger = Ledger::findByLegalEntity(CompanyInfo::find().RecId).RecId;
qbdsLedger = qbds.addDataSource(tableNum(DimensionAttrValueLedgerOverride));
qbdsLedger.joinMode(JoinMode::NoExistsJoin);
qbdsLedger.fetchMode(QueryFetchMode::One2One);
qbdsLedger.addLink(fieldNum(DimensionAttributeValue,RecId),fieldNum(DimensionAttrValueLedgerOverride,DimensionAttributeValue));
qbdsLedger.addRange(fieldNum(DimensionAttrValueLedgerOverride,Ledger)).value(strFmt("%1",ledger));
qbdsLedger.addRange(fieldNum(DimensionAttrValueLedgerOverride,IsSuspended)).value(SysQuery::value(NoYes::Yes));
//Add below code--
Reference:
https://community.dynamics.com/ax/b/meritmatters/archive/2016/01/28/financial-dimensions-lookup