How small do you want to make the Firefox window?

It should normally be possible to make the width quite small unless there are special buttons on a toolbar added by extensions that display extra info. I can get to a minimum width of around 200px.

Can you attach a screenshot?

• http://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

• Use a compressed image type like PNG or JPG to save the screenshot
• Make sure that you do not exceed the maximum size of 1 MB

For some of the things I do, such as collages, I need to go smaller than this. When I previously worked around this problem, I had to set a minimum window width.

This might be happening because of the Tab being in the title bar and what looks like a Firefox application button.

Does running Firefox in Safe Mode with all extensions disabled and possibly hide the title bar allow to make the window smaller?

Does it make a difference if you open the about:blank page?

I had forgotten to check my userChrome.css file for rules that override the min-width and see that I had a min-width set to 200px. I see that the default is 300px

• chrome://browser/content/browser.css

#main-window:not([chromehidden~="toolbar"]) {
  min-width: 300px;
}

Add code to the userChrome.css file below the default @namespace line. Adjust the min-width to suit your needs.

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#main-window:not([chromehidden~="toolbar"]) {
 min-width:50px!important;
}

The customization files userChrome.css (user interface) and userContent.css (websites) are located in the chrome folder in the Firefox profile folder.

• http://kb.mozillazine.org/Editing_configuration
• http://kb.mozillazine.org/userChrome.css

Now I think we are on the right path as this jogs my memory a bit. I did a little research and created a new file using Notepad, named it "userchrome.css" and think I saved it in the correct spot, But it doesn't seem to be working. Attached is a screenshot of the text file and the explorer window showing it's location. What did I miss?

The file type of the file is OK (Cascading Style Sheet), but the name is wrong and should be userChrome.css with an uppercase 'C'. You also need to create a chrome folder (note the lowercase chrome in this case) and move the userChrome.css file to this folder.

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\chrome\userChrome.css

That did it, thanks!