On top left corner, Firefox displays the Title of website that you are visiting. The same is shown in Firefox’s window in the taskbar. How can I customize what is shown in the title bar? How can I add some custom text in it?
For example, in below image, you can see two Firefox windows in the taskbar; each has a custom text that I have added. “Google” is the text in left window and “SERPS” in the second one.
Download the following add-on: Customize Titlebar
After installing it, go to Tools > Customize Titlebar Options. Use the forth option to add custom text in Firefox title-bar.
It’s a feature for power-users
For an average Joe, I cannot think of any reason why he would want to display custom text in Firefox title-bar; this is something website-designers, coders, programmers, webmasters, etc. may need. For instance, I use more than six separate/multiple Firefox instances/profiles. I use each instance for a specific work. Each instance has one or more windows and multiple tabs in it. Aforementioned add-on is a good solution for distinguishing between all the Firefox instances I use. It allows me to add any text to the title-bar; I can customize the title-bar in different ways.
If your work requires you to open many windows, then at a certain point, Windows start to reduce the size of each window title-bar. In this situation, it is best to either use very small custom labels using the aforementioned plugin or find some other solution because Windows can reduce the size of title-bar significantly. When this happens, then you won’t be able to manage all the windows efficiently. Instead of using long labels, you can use small ones; for instance, instead of “Google Webmaster Tools,” just use “GWTs.”
Using long labels present unexpected consequences
Using long labels limit visibility of the actual title of the website that you have opened in the window. This can present issues with detecting which window has what website opened in it. Labelling the title-bar is not always the best solution to distinguish between multiple Firefox instances.
Some useful resources!