The only initial UI - visible just after installing Firebug - is an icon placed at the bottom of the browser window, which I believe is the kind of minimalistic UI users want.
- The user deserves a clear result after the installation - "oh, there is Firebug now".
- The UI is minimal enough so it doesn't disturb the user when Firebug is not used.
(I am going to call this icon Firebug Start Button)
Another important role of this tiny UI is informing the user whether Firebug is currently activated (the icon is shining and colorful) or deactivated (grayed out). This is useful to know since having Firebug activated costs more CPU cycles. Also, don't forget, number of errors is displayed next to it (in case of any errors on the page).
Clicking on the icon opens the real Firebug UI and right clicking on it, opens a context menu with some actions that might be useful at this moment.
So, far so good.
The problem is that one of the goals of Firefox 4 is to get rid of the status bar. Sure, the bottom area will be still available (mostly for backward compatibility since Firebug isn't the only one using it). It'll be called an add-on bar and hidden by default.
I personally like the decision since it goes hand in hand with minimizing of the browser UI itself, which has been the trend for some time already.
Well, but what about the Firebug Start Button? Where we should put it?
One idea is to utilize the Firebug Toolbar Button that is available in the Customize Toolbar dialog. If you right click on Firefox tab-bar area (the location where a toolbar or menu bar are usually displayed) and pick Customize... you should get it.
Now you can drag-and-drop the button and put it into the toolbar or addon-bar (if you insist to use it).
This button would have the same functionality as the good old status bar icon (ie. clicking on it would open/close Firebug, the same context menu would be associated, the activation state indicated...) and would be placed onto the Firefox toolbar (or addon bar?) automatically after Firebug is installed (so, the 'ah, there is Firebug now' still works).
The previous position at the bottom was probably a bit more efficient, since now you have to go all the way to the top, but yeah, that's the price we pay for not having the status bar.
Would this work for you? How about the number of errors label? Where you would expect to have it displayed in case the add-on bar is hidden?
Would you rather prefer to have the icon at the bottom and keep the addon bar opened?
Any feedback here on the blog or on newsgroup appreciated!