Steps to reproduce:

1. Run the Workrave in Windows / Fedora 7
2. Change the micro-brake settings as follows:
   a. Time between breaks : 5 minutes
   b. Break duration : 15 seconds
   c. Postpone time : 2.30 minutes
   d. Maximum number of prompts : 15

3. After 5 minutes, micro-brake appears saying:
   
   Time for a micro-break?
   Disappearing in 30 seconds

   And then the "Disappearing in 30 seconds" count downs (I assume it should start counting down from 15 seconds

4. After 5-6 seconds, another dialog box appears, where the counting start from 10 or 9 seconds.

This is normal behavior.

The "Disappearing in 30 seconds" window (we call it a prelude) warns you that it is time to take a break, and asks you to stop working. If you like, you can use those 30 seconds to finish a sentence or anything.

After you stop working, Workrave takes about 4-5 seconds to detect that you actually stopped. If you stop working immediately when the prelude window appears, then those seconds are subtracted from your break time, hence your break time seems to cunt down from 10 or 9 or so, but you should notice that the progress bar is already one third filled, indicating the other 5 seconds of your break.

If you do not stop working when the prelude appears, but only a little later (say after you finish your sentence), then the 5 seconds workrave needs to detect that you stopped are not subtracted, hence your break will count down from 15.

This behavior is intentional as Kees-Jan mentions. Closing bug.