Is there an existing issue for this?

• I have searched the existing issues

Description of the Issue

Notepad++ v8.8.7 freezes and becomes unusable for a long period (up to 30 seconds) every time I switch to a tab containing a Perl file. The freezing is specifically caused by the built-in Function List panel.

The issue did not exist in older versions, such as v8.8.1.

Steps To Reproduce

1. Start a clean installation of Notepad++ v8.8.7.
2. Ensure the Function List panel is enabled (View > Function List).
3. Open any Perl file (even a small, simple one, e.g., 5KB, as long as it has a 'use' statement in it).
4. Open a second file (e.g., a new, empty tab).
5. Click the tab to switch from the second file back to the Perl file.

Current Behavior

• The entire Notepad++ window freezes, and the mouse cursor displays the hourglass/busy icon.
• The application remains frozen for approximately 20 to 30 seconds on every single tab switch to another file, whether or not it's a Perl file.

Expected Behavior

• Switching tabs should be instantaneous, as it was in previous versions (v8.8.1).

Debug Information

Notepad++ v8.8.7   (64-bit)
Build time: Oct 19 2025 - 16:19:15
Scintilla/Lexilla included: 5.5.7/5.4.5
Boost Regex included: 1_85
Path: C:\Program Files\Notepad++\notepad++.exe
Command Line: "C:\Program Files\Notepad++\functionList\perl.xml" 
Admin mode: OFF
Local Conf mode: OFF
Cloud Config: OFF
Periodic Backup: ON
Placeholders: OFF
Scintilla Rendering Mode: SC_TECHNOLOGY_DIRECTWRITE (1)
Multi-instance Mode: monoInst
asNotepad: OFF
File Status Auto-Detection: cdEnabledNew (for current file/tab only)
Dark Mode: OFF
Display Info:
    primary monitor: 1920x1080, scaling 100%
    visible monitors count: 1
    installed Display Class adapters: 
        0000: Description - NVIDIA GeForce GT 730
        0000: DriverVersion - 30.0.14.7212
        0001: Description - NVIDIA GeForce RTX 3050
        0001: DriverVersion - 32.0.15.7700
OS Name: Windows 11 Home (64-bit)
OS Version: 24H2
OS Build: 26100.6899
Current ANSI codepage: 1252
Plugins: 
    mimeTools (3.1)
    NppConverter (4.7)
    NppExport (0.4)

Anything else?

I think I've isolated the problem to a specific file change, likely introduced to address 'Fix #17043 (Enhance Perl FunctionList for class):

• The freezing issue is likely caused by the updated contents of the default configuration file: C:\Program Files\Notepad++\functionList\perl.xml.

• Workaround: Replacing the v8.8.7 perl.xml file with the version from v8.8.1 immediately and completely resolves the freezing issue.

I'd suggest a review of the regular expression logic in the classRange definition within the new Perl Function List file, as it appears to be causing a massive performance issue.