DB Tree filter: filter out strings ending with "smth"

So I was trying to filter out tables ending with "enum". I'm no expert in regexp but after some searching found working example:

.*(?<!enum)$

At least it works at regex101.
But when I try to use it in table part of db/table filter I get the following error:

/* TRegExpr(comp): Urecognized Modifier (pos 11) */

Did some tinkering, looks like it doesn't understand parentheses.
So the question is: can I do it some other way? Or can I hope for a fix (if it is possible at all)?

Just try this:

enum$

... Or this if you want to appear enum at the very left:

^enum

Looks like I wasn't very clear on what I was trying to do.
What is needed is to remove from table tree all tables ending with "enum". Not leave them in tree like "enum$" would do but remove them and leave everything else. To perform something like

%tablename% NOT REGEXP("enum$")

Any solutions?

Ah, sorry, I misunderstood the question.

I'm just testing a negative lookahead, but that doesn't seem to be supported by SynEdit's TRegExpr:

(?!enum)

Feel free to dive into the regex library from SynEdit, which HeidiSQL is using:
http://sourceforge.net/p/synedit/code/HEAD/tree/SynEdit/Source/SynRegExpr.pas