ImTranslator Button on the Toolbar appears right after ImTranslator extension installation.
When clicking the ImTranslator button on the Firefox toolbar, the ImTranslator application opens. By default ImTranslator application is linked with the Toolbar button.
If you want your preferred translation application to be run from the Toolbar button, you can set this application in Options Settings using Toolbar Button option.
1) If you set ImTranslator or Translator application on the Toolbar button, clicking the Toolbar button will open empty translation window where you can enter text to translate.
2) If you set Pop-up Bubble or Inline Translator applications on the Toolbar button, clicking the Button will produce the alert: "Please select text".
So, before running these applications from the Toolbar button, you have to select the text first in order to translate.
3) If you set Webpage Translation on the Toolbar button, pressing the ImTranslator button on the toolbar will translate a webpage.
Disable ImTranslator Button on Toolbar
If you don't use ImTranslator button on Toolbar and want to disable it, clear the checkmark box "Show ImTranslator button on toolbar" in Options Settings.