Firefox open messages while Chromium does not

Firefox open messages while Chromium does not

A strange phenomena has occurred.

Firefox opens mail messages while Google Chromium does not. This is the case on a Windows 7 laptop but it is the same on a Xubuntu Linux laptop. Both operating systems behaves the same way. So i guess it has to do with the browser.

Can any body enlighten what has happened and how to fix it.

Ingmar Forne, Finland