Stale Subtitles

According to XSTE’s man page, a blank line should remove the previous subtitle from the screen. But I noticed the last subtitle on a chapter was still displayed on the next chapter. The output of XSTE included the .bmp file for the last non-blank line, but nothing for the blank lines. A workaround is to put in a line with just a period in it, generate the output, then edit the .bmp (with GIMP) for that line and erase the period. Then running submux-dvd creates the blank subtitle, effectively clearing the previous line.