RRGparbank

To change a label, click on a node to select a different label from a list. The syntactic category and the function tag (before and after the dash "-") must be selected separately by clicking on the corresponding part of the label.
To add a function tag to a node that does not have one yet, drag it from the list of function tags onto the node.
Re-attach a node by dragging and dropping it on a new parent. This can be used to created discontinuous constituents.
Similarly, nodes can be removed and new ones added by dragging to/from below the tree.
Finally, the bracketing can be edited manually in the text box below the tree; press "validate" to update the tree. Whitespace is ignored. Each token must have a dedicated POS tag.

				[...wait for it...]

(SENTENCE
  (CLAUSE
    (CORE
      (NP (PRO-DEM 0=There))
      (NUC (V 1=was))
      (ADVP-PERI (CORE_ADV (NUC_ADV (ADV 2=even))))
      (NP
        (OP-DEF 3=a)
        (CORE_N (AP-PERI (CORE_A (NUC_A (A 4=whole)))) (NUC_N (N 5=sub-section)))
        (CLAUSE-PERI
          (CORE
            (NUC (V 15=engaged))
            (PP
              (P 16=in)
              (CORE
                (NUC (V 17=producing))
                (NP
                  (OP-DEF 18=the)
                  (CORE_N
                    (AP-PERI (CORE_A (NUC_A (A 19=lowest))))
                    (NUC_N (N 20=kind))
                    (PP
                      (P 21=of)
                      (NP
                        (CORE_N (NUC_N (N 22=pornography)))
                        (SENTENCE-PERI
                          (, 23=,)
                          (CLAUSE
                            (PrCS (NP-REL (PRO-REL 24=which)))
                            (CORE
                              (NUC (AUX-TNS 25=was) (V 26=sent) (PRT 27=out))
                              (PP-PERI
                                (CORE_P
                                  (NUC_P (P 28=in))
                                  (NP
                                    (CORE_N
                                      (AP-PERI
                                        (CORE_A (NUC_A (V-PART 29=sealed))))
                                      (NUC_N (N 30=packets)))))))))
                        (SENTENCE-PERI
                          (CLM 31=and)
                          (CLAUSE
                            (PrCS (NP-REL (PRO-REL 32=which)))
                            (CORE
                              (CORE
                                (NP
                                  (OP-DEF 33=no)
                                  (CORE_N (NUC_N (N-PROP 34=Party) (N 35=member)))
                                  (PP-PERI
                                    (, 36=,)
                                    (CORE_P
                                      (NUC_P (P 37=other) (P 38=than))
                                      (NP
                                        (PRO 39=those)
                                        (CLAUSE-PERI
                                          (PrCS
                                            (NP-REL (PRO-REL 40=who)))
                                          (CORE
                                            (NUC (V 41=worked))
                                            (PP (P 42=on) (NP (PRO 43=it)))))))
                                    (, 44=,)))
                                (NUC (AUX-TNS 45=was) (V 46=permitted)))
                              (CORE
                                (CLM 47=to)
                                (NUC (V 48=look))
                                (PP (P 49=at)))))))))))))))))
  (SENTENCE-PERI
    (. 6=-)
    (CLAUSE
      (PrCS (NP (CORE_N (NUC_N (N-PROP 7=Pornosec)))) (, 8=,))
      (CORE
        (NP (PRO 9=it))
        (NUC (AUX-TNS 10=was) (V 11=called))
        (PP
          (CORE_P (NUC_P (P 12=in)) (NP (CORE_N (NUC_N (N-PROP 13=Newspeak))))))))
    (. 14=-))
  (. 50=.))