Description of the Issue

Auto-completion (Word completion only) is too slow to use - If the word list is long, the box takes 2-3 minutes to appear.

Steps to Reproduce the Issue

1. Make the text file of 5-6 MB,
2. open in v8.
3. Set the following settings:
   
4. Type a character

Expected Behavior

The Auto-completion box appears immediately.

Actual Behavior

If the word list is long, the box takes 2-3 minutes to appear

Debug Information

Notepad++ v8 (64-bit)
Build time : Jun 6 2021 - 18:38:25
Path : C:\Program Files\Notepad++\notepad++.exe
Command Line :
Admin mode : OFF
Local Conf mode : OFF
Cloud Config : OFF
OS Name : Windows 10 Home (64-bit)
OS Version : 2009
OS Build : 19042.985
Current ANSI codepage : 1252
Plugins : mimeTools.dll NppConverter.dll NppExport.dll