Index Out Of Bounds in PdfAnnotatorV1

[coderarjob]

Stack Trace:

Exception :index -1, length 0
        java.lang.StringIndexOutOfBoundsException: index -1, length 0
        at java.base/java.lang.String.checkIndex(String.java:4560)
        at java.base/java.lang.AbstractStringBuilder.deleteCharAt(AbstractStringBuilder.java:970)
        at java.base/java.lang.StringBuilder.deleteCharAt(StringBuilder.java:298)
        at coderarjob.kpdfsync.lib.annotator.PdfAnnotatorV1.doHighlight(PdfAnnotatorV1.java:96)
        at coderarjob.kpdfsync.lib.annotator.PdfAnnotatorV1.highlight(PdfAnnotatorV1.java:65)
        at coderarjob.kpdfsync.poc.MainFrame$2.run(MainFrame.java:201)
      at java.base/java.lang.Thread.run(Thread.java:833)