**Steps to replicate the issue** (include links if applicable):
* I add in Options/Find and replace (box ticked)/Normal settings (regex box of the line ticked) :
Find:
```
^(\s*\|\s*)nom_mk (\s*=\s*)
```
Replace:
```
$1autres noms$2
```
* I connect AWB using my bot account to Wikipedia in French
**What happens?**:
On the page https://fr.wikipedia.org/w/index.php?title=Mojanci nothing is modified.
**What should have happened instead?**:
"nom_mk" should be changed to "autres noms"
**Software version** (skip for WMF-hosted wikis like Wikipedia):
**Other information** (browser name/version, screenshots, etc.):
The regex works on regex101 : https://regex101.com/r/LQUfdi/1
I made a "Reset to default settings" to no avail.
The Find and replace/Normal settings works with a non regex replacement (i.e. "nom_mk " => "autres noms", but I want to use regexes later, I didn't made tests with other ones yet.