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 0=It))
      (OP-MOD 1=must)
      (NUC
        (AUX 2=be)
        (ADVP
          (CORE_ADV
            (ADVP-PERI (CORE_ADV (NUC_ADV (ADV 3=round))))
            (NUC_ADV (ADV 4=about)))))
      (NP (OP-DEF 5=that) (CORE_N (NUC_N (N 6=date)))))
    (CLAUSE-PERI
      (, 7=,)
      (CLM 8=since)
      (CLAUSE
        (CORE
          (NP (PRO 9=he))
          (NUC
            (AUX-TNS 10=was)
            (AP
              (CORE_A
                (NUC_A
                  (ADVP-PERI (CORE_ADV (NUC_ADV (ADV 11=fairly))))
                  (A 12=sure))))))
        (CLAUSE
          (CLM 13=that)
          (CORE
            (NP (OP-DEF 14=his) (CORE_N (NUC_N (N 15=age))))
            (NUC (AUX-TNS 16=was) (NP (CORE_N (NUC_Q (QNT 17=thirty-nine))))))))
      (CLAUSE
        (, 18=,)
        (CLM 19=and)
        (CORE (NP (PRO 20=he)) (NUC (V 21=believed)))
        (CLAUSE
          (CLM 22=that)
          (CORE
            (NP (PRO 23=he))
            (NUC (AUX-ASP 25=been) (V 26=born))
            (PP
              (CORE_P
                (NUC_P (P 27=in))
                (NP (CORE_N (NUC_Q (QNT 28=1944) (CLM 29=or) (QNT 30=1945)))))))
          (OP-TNS 24=had))))
    (. 31=;))
  (CLAUSE
    (CLM 32=but)
    (CORE
      (NP (PRO 33=it))
      (NUC
        (AUX-TNS 34=was)
        (AP
          (CORE_A
            (ADVP-PERI (CORE_ADV (NUC_ADV (ADV 35=never))))
            (NUC_A (A 36=possible)))))
      (ADVP-PERI (CORE_ADV (NUC_ADV (ADV 37=nowadays)))))
    (CORE
      (CLM 38=to)
      (NUC (V 39=pin) (ADV 40=down))
      (NP (OP-DEF 41=any) (CORE_N (NUC_N (N 42=date))))
      (PP
        (CORE_P
          (NUC_P (P 43=within))
          (NP
            (NP (OP-DEF 44=a) (CORE_N (NUC_N (N 45=year))))
            (NP (CLM 46=or) (CORE_N (NUC_Q (QNT 47=two)))))))))
  (. 48=.))