void (@NotNull DocumentEvent event) { if (!myRangeMarker.isValid()) { myDocument2.setReadOnly(false); try { replaceString(myDocument2, 0, myDocument2.getTextLength(), DiffBundle.message("synchronize.document.and.its.fragment.range.error")); } finally { myDocument2.setReadOnly(true); } return; } CharSequence newText = myDocument1.getCharsSequence().subSequence(myRangeMarker.getStartOffset(), myRangeMarker.getEndOffset()); replaceString(myDocument2, 0, myDocument2.getTextLength(), newText); }