My joomla version is 3.6.5, Virtuemart is 3.0.19.1, theme is t3_bs3_blank, I found the product description is close in small screen, I want to keep it open, otherwise visitor will ignore it. Please help, many thanks.
That is an issue with your Joomla template, nothing to do with VirtueMart. And VM3.19.1 was a dev/test version, not a stable release version.