Certain pages or windows don’t appear in Outlook Web App or in the Exchange admin center when using Google Chrome

When you use Google to access Web App or the admin center, you’re unable to perform certain actions because certain pages or don’t appear expected.
For example, you’re an admin and you want to change a custom attribute for a mailbox. You open the properties of the user, and then under Custom attributes, you click Edit.
However, the page that lists custom attributes doesn’t appear.

Update the policy settings for the browser. To do this, follow these steps.

  1. Click Start, type regedit in the search box, and then click regedit.exe.
  2. Locate, and then click the following registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\EnableDeprecatedWebPlatformFeatures

    Note If the Google subkey is not present, create it manually. For steps on how to do this, see the More Information section of this article.

  3. On the Edit menu, point to New, and then click String Value.
  4. Type 1, and then press Enter.
  5. Right-click the 1 string value that you created, and then click Modify.
  6. In the Value data box, type ShowModalDialog_EffectiveUntil20150430, and then click OK.
  7. Exit Registry Editor.

http://support.microsoft.com/kb/3001145/en-us?sd=rss&spid=16662