If it turns out to be the other extensions that are disabling its use, you can enable the Copper Extension in Incognito Mode and use it in Incognito. If the above options do not fix your issue, the following can interfere with the extension.
In the Chrome menu, go to Preferences ⇨ Advanced ⇨ Privacy and Security ⇨ Clear Browsing Data.Below you will find some common fixes for any issues you may be experiencing with the Copper Chrome Extension for Gmail.
