I would very much like to see an option that can scan all my project files to see if one of these files has an extra space or enter attached at the end of a file after the php closing tag (?>)

We all know the problem that sometimes php returns an error in where it detects that 'the output was already started'. Most of the times it has to do with an extra space at the end of a php file.

I have a LOT of php files and sometimes there is indeed an extra space/return after the closing tag. It would be a timesaving function that detects and repairs such files.

Do you think this is a thing that can be implemented inside phped ?

Or even just an option to outright automatically remove any trailing blank lines. I've seen this in other editors, such as BBEdit.

Great idea ! Add my vote to this.

I was going to post that for now, you can clean your files up with the Find in Files feature by searching for the following regular expression:

(?m)\n+\Z

and replacing it with an empty string. However, when I tried to verify it, I found that PhpED's search engine seems to have a couple of issues.

The first is that it seems to treat every line of your file as its own independent search string even when you include the multi-line modifier. Put another way, it treats the above expression as though it were:

\n+$

which is completely different. (And of note, the \Z modifier should work globally even without the m switch, which means that the original expression tries twice to hit the end of the file versus the end of the line.)

The second problem, and this is probably related to the first, it doesn't seem to be able to find line feeds, using \r or \n. Thus, for the problem at hand, the IDE's search features would appear too limited to be of help. Sorry!

you may want to check www.php.net/pcre to see regexp syntax we support.
I agreed with the rest, we don't support multi-line search-replaces, including regexp-based.