How do we change which Browser is used for MettleCI Workbench?

The MettleCI Custom menu items invoke the MettleCI Workbench using your system default browser.

Inspecting the configuration of the Custom menus will show that they use the command explorer.exe to invoke the windows shell. This is not to be confused with Microsoft Internet Explorer. The explorer.exe executable refers to the Windows file explorer which, when invoked with a URL parameter such as those provided by the MettleCI menu items, will result in the current user's default browser being invoked to load the supplied URL’s.

To change the browser used to access MettleCI Workbench then simply change your default browser and this will automatically be invoked.