@Override
        public void verifyKey(VerifyEvent e)
        {
            if (readOnly) {
                return;
            }
            if ((e.character == SWT.DEL || e.character == SWT.BS) && isInserting) {
                if (!deleteSelected()) {
                    if (e.character == SWT.BS) {
                        startPosition += upANibble;
                        if (startPosition > 0L) {
                            content.delete(startPosition - 1L, 1L);
                            endPosition = --startPosition;
                        }
                    } else {  // e.character == SWT.DEL
                        content.delete(startPosition, 1L);
                    }
                    ensureWholeScreenIsVisible();
                    ensureCaretIsVisible();
                    Runnable delayed = () -> {
                        redrawTextAreas(true);
                        runnableEnd();
                    };
                    runnableAdd(delayed);
                    updateScrollBar();

                    notifyListeners(SWT.Modify, null);
                    notifyLongSelectionListeners();
                }
                upANibble = 0;
            } else {
                doModifyKeyPressed(e);
            }

            e.doit = false;
        }
Converts a hex String to byte[]. Will convert full bytes only, odd number of hex characters will
have a leading '0' added. Big endian.

@param hexString an hex string (ie. "0fdA1").
@return the byte[] value of the hex string
plugins/org.jkiss.dbeaver.ui.editors.hex/src/org/jkiss/dbeaver/ui/editors/binary/HexEditControl.java