Rudder

It seems that rudder UI do not like a SELECT field(metadata.xml) that could be empty such as :

      <SELECT>
        <NAME>CAPABILITIES</NAME>
        <DESCRIPTION>Add linux capabilities to container</DESCRIPTION>
        <ITEM><VALUE>SETPCAP</VALUE><LABEL>SETPCAP: Modify process capabilities.</LABEL></ITEM>
        <ITEM><VALUE>TEXST</VALUE><LABEL>TEST: Modify process capabilities.</LABEL></ITEM>
        <CONSTRAINT>
          <MAYBEEMPTY>true</MAYBEEMPTY>
        </CONSTRAINT>
      </SELECT>

In that case whenever you try to create/update/review a directive that didn't set a value in the select you got the nice spinning wheel for about 1 minute and a timeout error.