HTML email: cannot increase width

Question

In Thunderbird, plaintext emails are displayed normally: when I open the email in a separate window, and increase the window size, the text fills the whole width.

All HTML emails have fixed width, and increasing the window does not change the width.

And when I increase text size for better readability, this leads to comical results, where there are just a few words per line: see the screenshot

This is so idiotic. I assume there is [max-width][2] specified in that email somewhere, and Thunderbird does not allow me to display the message otherwise.

Or are there some settings in Thunderbird that can override that?

In any case, how can I change this absolute madness?

I am using Thunderbird 68.8.0 on Debian 10.

Answer 1

You're stuck in "zoom text only" mode.

Step 1

Go to View -> Zoom and uncheck "Zoom text only". You might have to close open tabs and/or restart thunderbird for this to have an effect.

Step 2

If that doesn't work, start thunderbird in safe mode by doing thunderbird -safe-mode.

If the zoom now works, one of your add-ons is the culprit: deactivate all of them, then re-activate one by one.

Step 3

If safe mode doesn't help, create a new profile or make a clean install.

• Creating a new profile
• Recover information from old profile

Additionally

You might also want to generally change the appearance size of the UI. You can do that in the config editor:

• Options/Advanced/General/Config. editor.
• Search for the variable layout.css.devPixelsPerPx
• Enter a value like 1.2, 1.4, 2.0. There are some pictures of how that will look in this answer

EDIT: Test of email zoom in TB 68.12 portable

zoomed in (CTRL+)

zoomed out (CTRL-)

Answer 2

I have managed to duplicate your email and I'm sorry to report that you cannot force this email to display in a wider format.

The problem is with the HTML contained within this email, which absolutely forces the width to be 550 pixels and no other.

The source of the problem is that the text is contained in a column that is inside an HTML Table. The definition of the table is (the interesting part is in bold):

<table id="wrapper" class="wrapper" width="100%" align="center" border="0" cellpadding="0" cellspacing="0" style="-webkit-font-smoothing: antialiased; font-family: Helvetica, Arial, sans-serif; font-size: 16px; max-width: 550px; width: 100% !important;">

The <table> tag contains a style= attribute which contains CSS rules. The max-width: 550px part within the rule forces the entire width of the table to be constrained within 550 pixels.

Now there are add-ons that can append CSS rules to the message which can override the max-width attribute. However, the writer of this message has destroyed any possibility of this by adding the !important keyword, which gives priority to his CSS over any external CSS. Using !important is very bad practice, especially since there was no need for it in this case.

The only way I can think of for changing the width of this email is to forward it to yourself. In the email composition dialog you will have the possibility for modifying the width of the included table.

Answer 3

There is a Thunderbird addon called Column Reader that allows users to resize the content of emails.

Works with Thunderbird 35.0 – 56.0

Screenshot 1	Screenshot 2	Screenshot 3
Examples of column layouts applied to the same Wikipedia page.	Panel with three sets of options for text, layout and color transformation (with panel themes at the right).	Panels of extensions developed by P.J.Sloetjes.

About this Add-on

Features

Column Reader makes reading a pleasure by providing the following features (see Screenshot 1):

• Paper, scroll and book layouts.
• Up to five columns for wide screens.
• Four different scrolling modes.
• Document miniature view in scroll bar.
• Replacement of fonts by a local font.
• Configurable color filters.
• Full screen image view with pan and zoom.
• Storage of settings for web domains.
• An intuitive content selection tool.

Usage

Column Reader adds a toolbar button which you may click 1) to enter the content selection mode or 2) to directly enter the reader mode in case options had already been saved for the current domain (see Screenshot 2).

To exit the reader, you may click the red bar within the reader, press ESC, or click the Column Reader toolbar button.

Within the reader, the following keys may be used to scroll: arrow left / arrow right / page up / page down / arrow up / arrow down / space / home. Reader areas that have a scroll function are recognizable by a custom mouse cursor. Content elements that can be scrolled horizontally show a horizontal arrow cursor.

Tips

• Left-click is disabled within the reader for safety (except for internal links), but you may still use right-click.
• In case content is too wide to fit a column, your best option is to reduce the number of columns using the options panel.
• Version 5.0 uses the GPU for color transformation, which may result in noticeably slower scrolling if your GPU is slow. If this is the case, you may want to use my extensions Colorific or Color Transform for page coloration (although these consume significant CPU time during color transformation).

About

Column Reader has been available since January 2012. Further development of this extension has been paused as of February 2017.