Can not adjust Gmail visual aspect in Firefox.

[Geek-9pm]

I do not think this is a OS issue. Maybe not even a browser issue. 

Whenever I go to gmail to check my mail, I have to adjust the font size by using the ctl+ combination to zoom in. (Like other seniors, I have the  low vision problem.)  Yes, I l could use the magnifier, and sometimes I do. Brut it is  more convenient to just user the zoom feature fouled in modern browsers.

Look at this:

(To conserve bandwidth I reduced the size of the image.)

Thee is no horizontal scroll bar, so I can not slide over to see the right side of the screen. But if I zoom out, the font is much too small for me to read. For some reason gmail thinks I would rather see the left sidebar instead of the text of the messages. Is this not a flaw in gmail? What can I do to make reading gmail easier.

Am I the only person that has this problem with gmail?   
Any help welcome.

[BC_Programmer]

This is an issue with G-mail that has been reported quite frequently on their issues pages. Often in different contexts. The usual reply is to blame the user for having the audacity to want to use their software in a particular way. "Reduce the size of your fonts" is not a solution, despite their repeated claims that it is. They should be fixing their software, not working up new ways to blame the user.

you might try the "basic" mode. It doesn't use any AJAX or javascript so it shouldn't be disabling the scrollbar. Browsers display the scrollbar when content is beyond the viewable area:

EDIT: Basic mode link:
http://mail.google.com/mail?ui=html

That said, the page might be explicitly disabling scrollbars. You would think browsers would have options to prevent this to workaround web designs created by egocentric companies who can't accept that their software might have issues, but I can't seem to find any.

[Salmon Trout]

In Chrome there is an extension to make the Gmail left sidebar resizeable, but you still won't get a horizontal scroll bar when zoomed so far that message text flows off the right side. Still you will see a bit more before that happens.  see here:

https://dottech.org/177566/how-to-resize-the-label-column-in-gmail-tip/

[Calum]

That said, the page might be explicitly disabling scrollbars. You would think browsers would have options to prevent this to workaround web designs created by egocentric companies who can't accept that their software might have issues, but I can't seem to find any.

In Firefox, this can be done using about:config.  There's a bevy of options beginning with dom.disable which stops websites from disabling certain features.  I used to set most of these to true (which disables this feature being disabled...) to eliminate popups with no close button, no title bar, and so forth.  This was before I started using Adblock Plus and now uBlock Origin, so I haven't actually set these options for years but I'm fairly sure they still work
dom.disable_window_open_feature.scrollb ars is the one in question here but some of the others may come in handy, they're fairly obviously named but a quick Google search will reveal more info if needed.
This link may also be handy as a reference: http://kb.mozillazine.org/About:config_entries#DOM.

[Salmon Trout]

dom.disable_window_open_feature.scrollbars

After I did this in Firefox I could zoom a message in Gmail and see a horizontal scroll bar up to 200% zoom, but it vanishes at the next zoom level (240%).

[Calum]

After I did this in Firefox I could zoom a message in Gmail and see a horizontal scroll bar up to 200% zoom, but it vanishes at the next zoom level (240%).

Ahh, Gmail is blocked here at work, so thanks for testing.

[Salmon Trout]

I always zoom using the CTRL key and the keypad plus and minus keys, and I have a Firefox add-on called Default Zoom Level, which shows the current zoom level in the top toolbar.

[Salmon Trout]

The zoom level steps in Firefox are a comma-separated list of decimal values held in about.config (toolkit.zoomManager.zoomValues). The default on mine seemed to be

0.3,0.5,0.67,0.8,0.9,1,1.1,1.2,1.33,1.5,1.7,2,2.4,3

so to get a more fine grained series I changed this to 0.1 steps:

0.3,0.4,0.5,0.6,0.7,0.8,0.9,1,1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9,2,2.1,2.2,2.3,2.4,2.5,2.6,2.7,2.8,2.9,3.0

I had to restart Firefox for this to take effect. Following this I was able to see that when zooming a message in Gmail the horizontal scroll bar previously enabled vanished out of the bottom of the Firefox window at 220% zoom level. If I then hit F11 for full screen Firefox I was able to get up to 240% still with a horizontal scroll bar. At 250% it vanished.

Note: my display resolution is 1920x1080

I don't know if these whole-screen grabs will show up properly:

At 240% zoom full screen:



For comparison, here is 100% zoom:

[Geek-9pm]

Thanks to
BC_Programmer, Salmon Trout and Calum. 
Because of your help,now I have  tools  to improve the visual layout of G mail.

[monicadawson]

Firefox gives you three in-built options—Enhanced, Classic, Blank—for the new tab. I have never been able to tell the difference between Enhanced and Classic, both of which appear in the speed-dial format. Anyway, you can do away with these default options as described below.
Get a Dedicated Add-on
There are several add-ons designed to put the New Tab page on steroids. Super Start is one of them and is quite popular. It gives you a visual way to maintain your bookmarks and also allows you to organize them into groups.
Super Start comes with a handful of muted themes. A tiny notepad and a list of recently closed tabs are tucked away in the corner. The add-on preferences allow you to set Super Start as your home page, view the speed dial in text-only mode, add a search box, etc.
 
New Tab Tools is also worth trying. It combines a speed dial with the launcher from the default home page. You can choose from a light and a dark theme, tweak the number and arrangement of tiles, and even add custom thumbnail images for the tiles.
If visual appeal is all you want to add to new tabs, you’ll love Browser Backgrounds. Every time you open a new tab, it randomly displays an interesting background from a predefined set. Add your favorite photos and wallpapers to the mix.
 
Personas Plus is another useful add-on to change Firefox skins quickly.
Add a New Theme
Firefox themes help you make Firefox feel like home. Install one that adds a nice background in new tabs or even allows you to add a custom wallpaper to them. Certain add-ons like Super Start and New Tab Tools (listed above) have an in-built setting to upload a background image of your choice.
Want to preview a theme before installing it? Just hover on its thumbnail on the themes page. Firefox will temporarily display the selected theme instead of the existing one.
 
Take the makeover a step further by choosing from one of the Complete themes that transform the look of various browser elements including tabs, menus, buttons, the address bar, and even the window frame. For example, FXChrome makes Firefox look like Chrome.
Home Page Makeover
The default Firefox home page is clean and convenient, but if you want to give it a personal touch, try one of the following alternatives.
 
Switch to Your Favorite Website
Setting up Firefox to load one of your favorite websites on startup is easy. OpenFirefox Preferences via Edit > Preferences, and in the General tab, look for theHome Page field. Add a link to your preferred website there. You can simply type it in or select it from your bookmarks.
If the page is running in the background, you can also click on Use Current Pages. Of course, this will set up multiple urls as home pages if there are multiple tabs open. This means that clicking on the Home button will load all of the pages listed in the Home Page field.
Want the default page back? Not a problem. Restore to Default will bring it back.
Hijack the New Tab Page
By default, you won’t see the home page unless you set it to load when Firefox starts or unless you press the Home icon. How about making it appear every time you open a new tab? Use one of the following methods.
•   Install a simple add-on like New Tab Homepage.
•   If you already use an add-on like Tab Mix Plus to manage tabs like a pro, make the home page your New Tab page from the add-on preferences.
 
•   Type about:config in the address bar, accept the warning that appears, search for browser.newtab.url, and change its value from about:newtab toabout:home.
 
Follow up this tweak by setting a super-useful star screen like Start.me as your home page.
Total Visual Control
The UserStyles.org website has a decent collection of themes for the Firefox home page as well as the New Tab page. Use it with the Stylish add-on and you can gain complete control over how Firefox looks. Here’s how you can go aboutimplementing user styles.
What Does Your Start Page Look Like?
Chrome does seem to have the upper hand when it comes to awesome start screens, but Firefox gives you more options for customization than any other browser. Take advantage of this Firefox freedom. Begin by tweaking that start page. It may or may not drastically improve your workflow, but it will brighten up your browser and give you some nice tools to work with.