Empty subtitle lines still displayed

[adicoto]

This bug is not related with the last build, but now I've remembered about it, working on a subtitle. When translating subtitles I often get into lines that have frames but not text

{100}{200}text
{300}{400}
{500}{600}text2
(800){900}

either because I wrote the frames but did not write the text or just imported frmes from another subtitle. So, when movie reach 300 frames and the subtitle line is empty, BSPlayer display the line "text" and when reaching line 800 it displays line "text2". I know that normally, a subtitle don't have empty lines but that is what is happens when it does have.