The text replace functionality works well, but there is an issue with the changes to firefox which added vertical tabs and the 'show sidebar' setting.
If we switch to vertical tabs or enable the sidebar then it adds an icon for this extension, and it cannot be removed or disabled.
Please update the extension to fix this or tell us how to have the sidebar visible without the extension icon.

Need checkbox :
start with,
end with,
keep case sizing,
and to take in consideration of lang="?" of html page pro list.

Auto case sensitivity, to adapt replacement to a term, without need to add multiple time the same term with letter variant (capital minuscule).

Like AutoHotKey ::TC0?:: ‖ ::TC0::

; ? (question mark) :
;--------------------
;The hotstring will be triggered even when it is inside another word; that is, when the character typed immediately before it is alphanumeric.
;For example, if :?:al::airline is a hotstring, typing "practical " would produce "practicairline ".
;Use ?0 to turn this option back off.

; C: (Case sensitive) :
;----------------------
;When you type an abbreviation, it must exactly match the case defined in the script.
;Use C0 to turn case sensitivity back off.

Adding new term in end of list is painful and could be reversed,

also sorting list would be cool,

and a checkbox to set a replace as important or not, to made them first.

To add U.R.L. filtering to prevent to act in some URL.

And to use import export, common standard format pro replace / correction, to be able to use them elsewere (Word, Write, other program of this kind).

'Potentially' the best add-on since Ublock Origin.
Now I can read pages in English, as opposed to the Universal State of Ambiguity that's rapidly replacing it!

Unfortunately, it's messing-up script-related (js) content.
Eg, Changing text/formatting colours, preventing js-related images, videos, etc. from rendering.

Finding more wrong with it as time goes by. It's becoming more annoying than the cause of the problems I installed it to remedy.

We could also do with the option to exclude specific domains.

Some clear and concise usage instruction would also be a welcomed addition.

Once the developer has finished the plug-in and fixed all the outstanding faults, I will compile a downloadable list to enable automatic US-American to English translation.

Due to the above issues, I have downgraded it to 3 until further improvements are made.
:-(

Although that I this is a very interesting extension and can be a time saver to many text writing users on the web, I gave only 3 stars because it can ONLY replace text and symbols in the text box of "Google translate" website only. It doesn't work on any other website, or Addon/extension which have full/or pop up text page input window. Also it takes two steps to do this job, whereas other similar Addons do this with one-click of the button. (here you must click the addon on the toolbar, click Replace from the list, and after a Sidebar will open on the right side of the window... which is too much of actions to do).
-> For now I will go with the two similar addons which are very convenient to me. Those are: ◾ Replace by erosman and the ◾ Find & Replace for Text Editing by Dalimil Hajek.
Fix this problem (to be able to replace text everywhere and make the process in only one step), and I will give 5 stars on my rating.

Very well to correct people's misspellings.
I would like the extension to correct the text on some url only.

Good for simple texts. I missed the possibility to save/view replace history and to replace large content in text areas like youtube description videos.

You must add at least one substitution and correct all errors
Все видимые поля я заполнил, что ей ещё нужно?

И ещё, хорошо бы менять только открытый для редактирования текст, а не отображаемый текст.
И эта версия почему-т не русифицированная, прежняя была лучше.

...it doesn't work with embedded Twitter tweets. At all. Even doing the manual "replace with substitution list" does absolutely nothing. I think this used to work, but not anymore.