Change Tempo - is this a glitch?

[dog8food]

using current version 1.3.13 on windows xp.

Sometimes when I change the tempo, it creates a space of silence at the end of the selection, instead of staying together with the unselected portion. But sometimes it doesn't. I understand that there's a speed change taking place, but why isn't it sticking with the remaining audio (yet sometimes it does)?

[billw58]

From the manual: http://manual.audacityteam.org/man/Change_Tempo

Due to weaknesses in its algorithm, Change Tempo can remove a very short length of content from the start or end of the selection, or not stretch the end of the content to the end of the selection when slowing down. Both of these symptoms may leave a short silence at the end of the resultant selection. To avoid this problem, you can use Effect > Sliding Time Scale / Pitch Shift... instead, setting initial and final tempo change to the same amount.

-- Bill