https://support.mozilla.org/en-US/questions/1269361

Thank you for your very prompt reply.

From the helpful pictures I can see this solution has worked for other folk. I feel I resolution must be close - using config.editor - but for me it didn't work:-

Modifying the value as suggested immediately made the font of the about config" screen I was looking at, bigger. Yipee, I thought.

But sadly modifying the value didn't change the font size of the opening / main screen of TB. By this I mean the screen that lists Inbox, sent etc folders on the left with a list of messages in the middle.

I wonder is it possible that another item in config.editor could be the answer to my problem.

Run TB in safe mode (hold Shift when you launch TB) and see if the Folder Pane and Threads Pane fonts scale with the rest of the fonts. This will test whether you have an add-on or userChrome file, or broken layout, that is affecting the change to the preference.

I just opened TB in Safe mode and the font size in the main screen (Folder Pane, Threads Pane) remained small. But the page where I used the confiig editor were stil in larger font. This followed my changing the layout (per your tip) from 1 to 1.3.

Thank you

Try different values, e.g. 1.5, 2.0, 2.5. There is no single value that suits all screens. The pictures I posted apply to a 22" 1680x1050 screen with default W10 display settings.

Dear sfhowes,

Problem solved. Thank you so much for your help. This is what fixed it:

(1) Per your suggestion going through Tools-> Options-> Advanced-> config.editor I modified layout.css.devpixelsperpx to value 1.5.

- this only changed the config.editor screen but had no effect on the main inbox/sent/folder pane that I had difficuty reading.

(2) Experimenting, I then went to mail.folderpane.size.units and modifed the value from blank to 1. Only then did (1) above have any effect on the main inbox/sent/folder pane. So I then experimented further, with the above value of 1.5. I tried 1.3 which was too small and then I tried 1.7 which was too large. Then I felt 1.5 was just right - as the goldilocks story goes.

I am amazed and thank you for your tips and motivation. If I hadn't been able to fix this I would not have been able to stay with Thunderbird.

what is the key for text size of incoming mail

TIA Renato

renato.pontefice said

what is the key for text size of incoming mail TIA Renato

Tools/Options/Display/Formatting/Fonts & Colors/Advanced..., set the Sizes and fonts with Fonts for: Latin and repeat with Fonts for: Other Writing Systems. Uncheck 'Allow messages to use other fonts'. Sizes are in pixels, not points; 12pt is about 18 pixels.