Steps to reproduce

1.  Create a dialog with a Twin-column field ($type twinColSelectField)
2.  Populate it with more than 500 items

Expected results

Unlimited number of items should be possible

Actual results

Error: «Client tried fetch more rows than allowed. This is denied to prevent denial of service»
RcpInvoctionException: Unable to invoke method requestRows in com.vaadin.shared.data.DataRequestRpc

This is a known vaadin bug introduced in 8.14.x. The solution seems to setMaximumAllowedRows  on the DataCommunicator

Workaround

None. It's a blocker for us because we have more than 500 usergroups in the security app and will lose the ability to assign groups to users after an upgrade to Magnolia 6.

Development notes