I'm not sure which visual element you're referring to. Here I get a rectangular pop-up window to tell me about new messages. It has a blue border, the Thunderbird logo and some text. Is it this that you want to adjust?

I know that many of Thunderbird's icons are buried in a strange file named omni.ja, and it is possible to extract images, modify them and save them back into it. "omni.ja" is actually a .jar file, and this can be opened and manipulated by many zip utilities.

I've done this for myself, but I am not seeing the new mail notification image that I played with appearing anywhere. Perhaps if you can offer a screenshot of the notification you see then I can identify the related artwork.

Another approach might be to try another notification system. This add-on:

https://addons.mozilla.org/en-US/thunderbird/addon/gnotifier/

adds Thunderbird's notifications into the regular system notification. I use it in both Linux and Windows 10 and it pops up rather large rectangular panels summarizing new messages. They are actually a bit intrusive, often appearing over the top of what it is you're trying to work with. In Windows 10 they can also appear in the large notification panel that pops up from the task bar.

Hi Zenos,

Thank you for replying.

I don't mean the pop-up. I mean the "new mail" icon that sits in the system tray, alongside the volume icon and the clock. Image attached.

Averill

So, would changing just the white of the envelope to red be useful?

Currently this icon has a transparent background. We could make that an opaque solid colour so the whole thing was a red square. Ugly, perhaps, but certainly eye-catching.

A difficulty with making a change to the omni.ja file is that it would be replaced each and every time Thunderbird is updated, so you'd have to apply this change at each update.

Yes, changing the white of the envelope to red would be ideal. Ugly or not, it would be very useful to me. I'm surprised there are no add-ons that do this.

Having to change the icon every time Thunderbird is updated cancels out (for me) the usefulness of having a more prominent icon. What a pity it's such a faff to change.

Thanks anyway

We could probably set up a simple batch file to replace the standard icon with the modified version. I'll have a look for your icon later today and see if I can make it work.

Many thanks, Zenos.

Adapting the icon is the easy bit for me. Finding it (and omni.ja) and replacing it in my profile is the challenging part for me. I'm a dab hand with graphics and image software, but a relative amateur under the hood of computers.

I can't find that icon in omni.ja - I'm starting to think it belongs to the operating system and may not be determined by Thunderbird.

Have you tried the add-on?

The add-on didn't make any difference to incoming new mail. It's a bit of a sledgehammer-to-crack-a-nut solution.

That white envelope icon does seem to be associated with Thunderbird -- that's the name it's listed under when I select icons to appear on the taskbar.

I've found a workaround for now: make the taskbar and system tray a dark colour (currently dark grey). It's makes the white envelope icon stand out more than it did before, although it's similar (with poor vision) to other white icons in the system tray.

Thanks for your help Xenos :)