[BioC] edgeR output figures

[Wang, Li]

Dear List Members

When I utilized plotSmear function to plot all the logFCs and highlight the DE genes, I got a figure with two tails shown in the attachment. 
The "tails" are composed of a lot of orange points (tags) and some red tags. 
I am considering that it might be caused by the loose filtering criteria. The one I set is as follows:
d <- d[rowSums(d$counts) >= 31,]
In total, I have 31 samples. 
I want to remove the tails from the output figures.
Any comments are very appreciated.

Thanks in advance!

Best regards
Li