Lead Converter LeadSource picklist only pulls values from 100 most recent leads

[njjc]

Line 83 in ONEN_CTRL_LeadConverter getSources method uses this query:
[select leadSource from lead where leadSource != null and isConverted = false order by createddate desc, leadsource limit 100]

This means that only the LeadSource from the most recently created 100 leads are available. A Group By clause would include all LeadSources, although I'm not sure if this could hit limit issues:
[select leadSource from lead where leadSource != null and isConverted = false group by leadsource limit 100]

I tried this in Dogwood's instance with >10k unconverted leads and didn't hit any limits.