[Feature Request] Add option to hide icon unconditionally in the menu
This feature is useful for Unity users, who already have an integrated Thunderbird icon in the system, as well as indication of new messages and notifications. A second icon is an excess, and I would like to deactivate the use of FF icon.

This issue has been previously mentioned in #137, #164 and #150.
There's no need of this feature in my opinion. Just define under "Symbol" a user defined icon and leave this entry empty -> No icon in addition to the indicator ;)
Sorry, your proposed solution does not work. After leaving custom icon entry empty and closing thunderbird (actually sending the program to the tray), the default icon reappears automatically.
@Zranz hm sorry, it works for me :/ I use FireTray v0.6.1 with v45.2.0 Thunderbird on 16.04 Xubuntu
Yeah, I cannot make it disappear. I use Ubuntu 16.04, so the difference may be I am using Unity desktop. Thanks.
I just tested it with an 1x1px transparent png and it also worked on Xubuntu. Maybe you could try this ;). I attached the used image. Download: [https://cloud.githubusercontent.com/assets/14253537/17790634/a80d538a-6597-11e6-8cc8-57b522958d8a.png]

Strange, it does not work. I tried different png's and none worked, default icon was present all the time.
Ok, that's really strange :/ What you also could try is to change the default icon under ~/.thunderbird/xxxxxx.default/extensions/firetray-id/chrome/skin/icons/linux/hicolor/22x22/apps/thunderbird.png (not sure but i think this is the default icon that is used by FireTray).