Hi, sorry for forgetting steps to reproduce the bug.

Easiest way to see it is to start redemo.py from a console (important on windows), so you can see stdout/stderr.
Then just a click on any of those flag checkboxes leads to an exception backtrace printed on the console.

And to demonstrate that the flag checkbox does not work, enter ".*" (without quotes) as the pattern, and any multiline string as the string to search, and activate the checkbox "MULTILINE".
Correct behaviour: no exception, all lines of the string get highlighted as the first match
Erroneous (actual) behaviour: An exception traceback gets printed: '_tkinter.TclError: expected integer but got "RegexFlag.MULTILINE"'
and only the first line is highlighted as first match, demonstrating that the MULTILINE flag is in fact not active.


When it comes to a pull request, I could do that for the change that I proposed. But regarding the "LOCALE" flag, the better solution (in my opinion) would be to make it work instead of just removing it, but that is a more elaborate change that I am not able to spend time on.

What would you suggest?
a) I provide a pull request, leaving "LOCALE" flag behaviour broken
b) I provide a pull request, removing "LOCALE" flag (to be introduced again when someone is willing to fix it)