Hello,
Great extension, clever operation. However, I found several bugs. Firstly, when the extension encounters a "/", it cuts the string and only sends the beginning to the translator. Secondly, very often hovering over the selection has no effect, other than reloading the background tab over and over again, with no popup appearing (especially when selecting a whole paragraph by triple-clicking). Finally, when hovering over the right edge of a translated popup (for example to reach the scroll bar), it tends to shrink and escape the cursor.
As an additional suggestion, it would be useful to be able to easily deactivate the extension with a button, to avoid hindering the selection when no translation is needed.