This is not actually a Thunderbird question, but a browser issue, so you should really be asking this in the Firefox forum (assuming you use firefox) as it is the browser taking the focus.

However, here is some help if you use Firefox.

If you use Firefox: type : about:config into the Firefox address bar and hit enter. you will get a warning to be careful :)

In the Search bar, type : diverted look for this line: "browser.tabs.loadDivertedInBackground"

By default, the value of this entry is false. To change it, double click on that line and it will toggle the value from 'false to 'true'. Restart Firefox .

Thank you. Worked like a charm!

I know I can't have my cake and eat it, but now when I click a link in an email, it looks like it didn't do anything at all (because my browser is on another desktop and I can't see that the tab was opened).

Since I was doing the action in Thunderbird, I posted here. I had no way of knowing that the issue was with Firefox.

I have been fooling around with config files (prefs.js) in both applications for years and still know what relatively few of the entries do. If someone would write a book on it, I'd buy it!

I know there are some references on the web, but not with very much detail. They just say what each one is - for the ones that are documented.

AFAIK, there's nothing that explains how to use them in a problem-oriented fashion.

It took me forever to get my page margins working properly for my printers. There are about a dozen related parameters and I'm still not entirely sure how it works.

I'm not aware of any complete reference to all preferences that offer a full explanation of what each does, what the Value means and how to use in a problem-oriented fashion.

But the list below does help: http://kb.mozillazine.org/Category:Preferences http://kb.mozillazine.org/About:config http://kb.mozillazine.org/About:config_entries http://www-archive.mozilla.org/unix/customizing.html#ui http://preferential.mozdev.org/preferences.html

there is also a postscript module used by eg: linux http://kb.mozillazine.org/PostScript_Module

Margins are set up here: File > Page Setup > Margins & header/Footer or via File > Print Preview > Page Setup button

Helpful hints: if you have Margins (millimeters) and set eg: Bottom margin as 20.0 then look in config editor, you will see: print.printer_XX.print_margin_bottom; Value = 0.787500023841858

This seemed odd at first. All Values in config were being converted to inches represented in a decimal format.

If you ever need to change the margins from millimeter to inches: Print.printer_xx.print_paper_size_unit Value: = 1 Change the Value to 0 (zero) to get inches

If you change the Value to 0 for inches and then reopen: File > Page Setup > Margins & header/Footer you will see the Bottom margin has auto changed from 20.0 (mm) to 0.8 (inches rounded up), so although the display is different in File > Page Setup > Margins & header/Footer tab, the actual information in config preferences remains unchanged as it is saved in decimal inches format used by US as default.

if using millimeters then the paper size would be A4 210 x 297 mm. Although looking in the config preferences it will say paper width 8.50 and paper height 11.00. Usually, you can change the paper size when you select to Print and look in Print Properties. I'm in UK and using millimeters so get A4; the US uses Letter 8½ x 11 inches.

So I can see how it could be confusing to anyone using millimeters and then sees, what appears like wrong data in preferences.

Thanks for all the links. I haven't checked them out yet, but I've probably already used a few of them.

I got around the millimeters thing long ago - got most of it to work in inches.

What throws me is that there is an unprintable margin, a header margin and a body margin and all of those get duplicated at least 6 times and for two dimensions - for every real and virtual printer the application has ever seen.

When I add a new printer, I invariably have text clipped off either side of the page and things like headers printing over body text.

There is no way AFAIK to actually fix this from the gui (although there is a dialog that tries to). I have to go into prefs and look at the last printer that works right and experiment with setting the values for the new one based on what worked before.

It used to take me many hours and many attempts to get it right. Now, having done it so many times, I usually can muddle through it in less than an hour.

It would be great if the gui really worked for this and actually showed me how all these parameters affected the resulting print. It tries to do some of that, but not enough to actually work.

As for the rest of the references I have seen so far, they're "references". (References are documents that remind you of the details of things you already know how to do.) They list parameters and sometimes list what the acceptable values are and maybe even what they actually do, but I have to guess what parameter to look at in the first place and this is especially difficult for the many optional parameters which aren't even in the stock config files to begin with. First, you have to discover them somehow and then add them manually.

It beats the heck out of having to study and then modify and rebuild the applications from source. I'm glad they're there. But they're sure not easy to use.