Plugins Button has been updated to version 3.1.
There is one notable new feature in this version: you can now change the toolbar icon to better fit your browser's theme. You can select from several different versions of the icon: red, green, orange, nude and the default blue icon. To do this just go to extension's settings page and select the icon you like.
To access the options page:
1) Right-click on the extension's icon and select "Options":
2) And select the icon from the list: