[TAB] is a regular expression meaning to exclude any of the three letters placed in the square brackets.

If you really want to exclude [TAB], you must enter it differently: (?:\[TAB\])

This is also a regular expression, using a so called non-capturing group, where the content in the round brackets is treated in the entered order.

To have \q excluded, you must "escape" the special character \ by entering \\q

To deal with all the elements you want to exclude you need to learn how regex works or give this to someone able to deal with that.

Thank you Jerzy Czopik for your advice. It works as expected now, which is really great!

What is the best way to learn regex rules? Are there are any tutorials or training couses, you'd recommend? Thank you in advance for your support.

You can start with https://www.regular-expressions.info/ and look also at the blog by Paul Filkin (https://multifarious.filkin.com/) where you find excellent examples for regex usage in Studio.

You can also visit the BP22 conference in Lisbon, where I will have a workshop on regex: https://bpconf.com/bp22/

There will certainly be more to be found on the net, but for the moment these are the resources I remember best.

Thank you! I'll certainly take a look, as I need more and more regex rules in my daily work.

I have also uploaded some introductory (and not so introductory) regex-related documents in the Facebook Trados Files section.