**Steps to replicate the issue**:
* Open new comment/new topic tool (DiscussionTools) in a Linux X system (don’t type anything for now).
* Click on “Visual” tab to switch to visual mode (in case you were in source mode).
* Copy some text in clipboard (Ctrl+C).
* Select some text, this is primary selection.
* Do not click on the surface (i.e. do not give it focus for now). Instead, directly paste the primary selection (mouse middle-click): the surface now only contains what you had selected. It also gets focus: a caret blinks after the inserted text.
* Optional: Type "abc": "abc" is well appended right after content you’ve pasted. You can also move the cursor and type other text somewhere else.
* Paste the clipboard (Ctrl+V).
**What happens?**:
Clipboard content is pasted at the start of the surface (before what you have already pasted and typed).
**What should have happened instead?**:
Clipboard content should be added where your cursor is located.
**Other information**:
Follow-up of {T316054}.
Same issue on Firefox and Chromium.