You may find it helpful to install a theme, which changes the appearance of Firefox's chrome (the visible parts of the program.) From the Firefox menu bar, see:

     Tools > Add-ons > Get Add-ons

or browse

https://addons.mozilla.org/en-US/firefox/themes/large?sort=rating

See also the help article Accessibility features in Firefox - Make Firefox and web content work for all users

If this answer has solved your problem, please mark the question as "Solved". This way you will help others in a similar situation.

thank you but i just want that menu to be bigger

The size of the context menu is set within the program's user interface (UI). Themes can change the UI so that things like the context menu appear with larger type, so a theme may be the easiest way for you to achieve your goal.

Another method is to increase the value of the configuration item called layout.css.dev (in pixels).

In current Firefox versions this is a text value you can adjust to fine tune the dimensions of all elements (user interface and web pages) more precisely.

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website. If you see a warning then you can confirm that you want to access that page.

Use the Filter bar at to top of the about:config page to locate the value by typing in "layout.css.dev" (without the quotes)

Right-click on that item to Modify and change the value to something from 1.0 to 2.0 in 0.1 or 0.05 steps to adjust the size of all fonts and other elements in Firefox.

Once you're done, the new setting will appear in bold type to show that it was changed.

Preferences can be reset to the default via the right-click context menu if they are user set, or by double-clicking on the item to reset the item to its default.

Please post back here if this was of help to you.

i did that but it;s not what i want

i want the menu when you RIGHT CLICK on a link or in a blank space in a web site

The menu you get when you right-click on a link is called the context menu. Did you try the above and did it increase the size of your context menu?

You can also change the size of individual elements in the UI by editing a file (you must create it if it does not exist) called userChrome.css.

-> Create file userChrome.css in a folder named chrome in your Firefox Profile Folder

   http://kb.mozillazine.org/UserChrome.css
   http://kb.mozillazine.org/Profile_folder

The menu you get when you right-click on a link is called the context menu. Did you try the above and did it increase the size of your context menu?

only changed the tabs and everything up there.

and about You can also change the size of individual elements in the UI by editing a file (you must create it if it does not exist) called userChrome.css.

way to difficult

Use this extension to adjust the font size for the user interface:

• Theme Font & Size Changer: https://addons.mozilla.org/firefox/addon/theme-font-size-changer/

thanks but that is not what i want

Try this code in userChrome.css below the default @namespace line.

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

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

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

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

#mainPopupSet menuitem { font-size: 13pt !important; }