Recently users working in older versions of Sitecore CMS have noticed that some features of the CMS stopped working in the latest version of Chrome (version 37+). The root cause of the issue was that Google has deprecated the showModalDialog() function that Sitecore relied on in versions 7.0 and previous. Starting in Sitecore 7.1 the functionality has been changed and is not an issue.
Up until yesterday Sitecore was recommending that all users either upgrade to 7.1, stop using Chrome, or apply a short-term fix to Chrome to temporarily re-enable this deprecated feature (see this blog post for more details -> http://www.bugdebugzone.com/2014/08/sitecore-modal-pop-ups-are-not-working.html?m=1).
If you are unable to upgrade to 7.1 (Note: if you are upgrading you should really consider moving to 7.2 update-2), then these patches seem like a good options to resolve issues with browsers that remove the showModalDialog() function.
Links to patches:
KB Article 581527