There is no uniqueness check when adding properties in "New resource" wizard. Thus it is possible to use the same key multiple times and consequently the creation process will fail with an error. User will also lose all entered data.

An example of such behavior is declaration of properties when creating new XA Datasource

How to reproduce:
1) navigate to XA datasources page
2) start creating new XA Datasource
3) In property declaration step create multiple properties with the same key
4) finish the wizard

expected result: user is not allow to use the same key multiple times in property declaration step
actual result: creation process is finish with error