In the Dev Tools, when I click on the New Style Rule button (the little "+" on the top right of Dev Tools' window) Chrome switches into "Aw, Snap!" mode: the whole page becomes grey with the sad Chrome icon in the middle.
If I disable AdBlock, or add the site to the whitelisted domains, I can add a new style without any issue.
[Duplicate] Issue with Add New Style in Chrome Dev Tools
Re: Issue with Add New Style in Chrome Dev Tools
Seems to work fine for me, both with the released version and the development build. Please provide more information: Chrome version, operating system, Adblock Plus version (I assume that you are using Adblock Plus and not Adblock).
Re: [Duplicate] Issue with Add New Style in Chrome Dev Tools
Never mind, there is another report of the same issue that has more info: forum/viewtopic.php?f=11&t=9811
Marking this one as Duplicate.
Marking this one as Duplicate.