private void ensureWholeScreenIsVisible()
    {
        if (textAreasStart + bytesPerLine * numberOfLines > content.length())
            textAreasStart = content.length() - (content.length() - 1L) % bytesPerLine - 1L -
                bytesPerLine * numberOfLines_1;

        if (textAreasStart < 0L)
            textAreasStart = 0L;
    }
While in insert mode, deletes the selection

@return did delete something
plugins/org.jkiss.dbeaver.ui.editors.hex/src/org/jkiss/dbeaver/ui/editors/binary/HexEditControl.java