code: def OnUpdateUI(self, evt):
          
  
          # check for matching braces
          brace_at_caret = -1
          brace_opposite = -1
          char_before = None
          caret_pos = self.GetCurrentPos()
  
          if caret_pos > 0:
              char_before = self.GetCharAt(caret_pos - 1)
              style_before = self.GetStyleAt(caret_pos - 1)
  
          # check before
          if char_before and chr(char_before) in "[]{}()" and \
             style_before == stc.STC_P_OPERATOR:
              brace_at_caret = caret_pos - 1
  
          # check after
          if brace_at_caret < 0:
              char_after = self.GetCharAt(caret_pos)
              style_after = self.GetStyleAt(caret_pos)
  
              if char_after and chr(char_after) in "[]{}()" and \
                 style_after == stc.STC_P_OPERATOR:
                  brace_at_caret = caret_pos
  
          if brace_at_caret >= 0:
              brace_opposite = self.BraceMatch(brace_at_caret)
  
          if brace_at_caret != -1 and brace_opposite == -1:
              self.BraceBadLight(brace_at_caret)
          else:
              self.BraceHighlight(brace_at_caret, brace_opposite)
docs: Syntax highlighting while editing