Am I correct that there is no existing keyboard shortcut (either in the Firefox Plugin or in the master application as a global shortcut) to generate a new password? This is a task I do frequently that I would prefer to handle without having to navigate with the mouse. If this feature doesn’t exist, please consider adding – I assume it would be a relatively quick fix.
Ctrl + Shift + 4 
Does this need to be enabled somehow? CTRL-Shift-4 has no effect for me right now.
Figured it out – I just wasn’t pressing it in the right form field. Ctrl-Shift-4 does bring up the password generator dialog box, but after selecting the generation algorithm, focus does not return to the form field – instead I need to click the mouse again or tab/shift-tab to get back to the form field. This seems like a bug in the plugin; ideally, you would go right back to where you were, which is presumably where you wanted to paste the newly-generated password.
I agree that re-focussing the previous form field would be a nice improvement so I’ve added a GitHub issue with a summary of how it could be implemented: https://github.com/kee-org/browser-addon/issues/289