At the dialog box of “Silence Finder”, Minimum duration of silence {seconds] seems to be limited as >= 0.10 seconds. The slider does not set the value to less than 0.10 seconds. I can yet type the value of less than 0.10 seconds into the box, but once I close the dialog box and re-open it, the value forced to set as 0.10 seconds.
But I want to find the silence value of less than 0.1 seconds.
Recently I found that I can find shorter time of the silence if I type the number of less than 0.10 seconds on the dialog box even though the value can not be stored. The smaller duration value seems to be available internally, but only the user interface seems to deny it.
Is my assumption correct ? Is it possible to activate the smaller silence duration on the user interface on the future update ?
You’re correct.
Until quite recently the minimum duration of silence was 0.1 seconds. Settings smaller than that are only rarely useful (special case situations). The danger of very small settings is that it can produce a huge number of labels. In the extreme case a label could be created each time the waveform crosses zero, which could be thousands of labels in each second of audio. Audacity is not designed to handle that many labels so that would not be good.
However, the effect was in need of some attention and I thought that it would be useful to accommodate those “special case” situations so while I was updating it I also added the ability for the minimum silence to go down to around 0.01 seconds. So as not to inconvenience the majority of users, the slider range was kept with a minimum duration of 0.1 seconds, but for those “special cases” the user can enter a smaller value by text input.
Note that the effect is only accurate to about +/-5 milliseconds, so if you set it to 0.02 seconds, then that actually means “about 0.02 seconds” and not “exactly 0.02 seconds”. Nevertheless, that’s a lot better than it used to be 
Fortunately it is very easy to modify this tool, because it is a “Nyquist Plug-in” and is written as a simple plain text file.
If you look in the Audacity plug-ins folder (inside the Audacity installation folder) you should find a file called SilenceMarker.ny.
Make a backup copy of that file, then open the original in a plain text editor (such as “NotePad” if you are on Windows).
14 lines down you will see the line:
;control sil-dur "Minimum duration of silence [seconds]" real "" 1.0 0.1 5.0
This line specifies the Minimum duration silence control.
The three numbers at the end of the line specify the slider default and slider range:
The default is 1.0 seconds
The minimum range is 0.1 seconds
The maximum range is 5.0 seconds.
Do not set the default or the minimum to less than 0.01
If, for example you want to change the slider settings to:
default = 0.1 seconds
minimum range = 0.01 seconds
maximum range = 1.0 seconds.
then you would change that line to:
;control sil-dur "Minimum duration of silence [seconds]" real "" 0.1 0.01 1.0
Then save the file.
Ensure that the file extension remains as .ny
Thank you very much. It worked well.
Your suggestion was just I want to.